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Developing the Schedule

(Premium)

Teaching Strategies

The first vignette reinforces the need to interact with community members and key stakeholders when planning the schedule. Sometimes part of the solution of the project is the creation of other beneficial projects to help with buy in.
The second vignette reinforces that the first design of a project might not be the final plan. Complex projects require creative solutions to keep all the aspects on track and the project to be completed on time and within budget. Even though it had difficulties and a few failures at the start, the complex project was scheduled well.
Sometimes, when planning the schedule, calculated times are for activity completion are not accurate. This can become a problem when no one takes the time to examine the actual time it takes to complete activities.
Have students plan the amount of time that it would take to travel between two cities that are near campus. After they calculate the time to travel, have them think about how they would factor in extenuating circumstances (like a flat tire, the need to refill the fuel tank, the need to stop for food, or a traffic-blocking accident).
Have students calculate the ES, EF, LS, and LF times in class to be sure they understand what it means to calculate forward and to calculate backward.
The ES, EF, LS, LF times on the network diagram for the consumer market study are included in the chapter materials. Have the students compare the textbook diagram with the schedule table in Microsoft Project.
Have the students report on the similarities and the differences.

Chapter Concepts

Estimating the resources required for each activity

Estimating the duration for each activity

Establishing the estimated start time and required completion time for the overall project

Calculating the earliest times at which each activity can start and finish, based on the project estimated start time

Calculating the latest times by which each activity must start and finish in order to complete the project by its required completion time

Determining the amount of positive or negative slack between the time each activity can start or finish and the time it must start or finish

Identifying the critical (longest) path of activities

Performing the steps in the project control process

Determining the effects of actual schedule performance on the project schedule

Incorporating changes into the schedule

Developing an updated project schedule

Determining approaches to controlling the project schedule

Implementing agile project management

Chapter Concepts

This chapter discusses monitoring and controlling the progress of the project, re-planning, and updating the project schedule.
Once a project actually begins, it is necessary to monitor progress to ensure that everything goes according to schedule. This involves measuring actual progress and comparing it to the schedule.
If at any time during the project, it is determined that the project is behind schedule, corrective action must be taken to get back on schedule, which becomes increasingly difficult as a project falls further behind.

Based on the material in this chapter, students will become familiar with:

Estimating the resources required for each activity
Estimating the duration for each activity
Establishing the estimated start time and required completion time for the overall project
Calculating the earliest times at which each activity can start and finish, based on the project estimated start time
Calculating the latest times by which each activity must start and finish in order to complete the project by its required completion time
Determining the amount of positive or negative slack between the time each activity can start or finish and the time it must start or finish
Identifying the critical (longest) path of activities
Performing the steps in the project control process
Determining the effects of actual schedule performance on the project schedule
Incorporating changes into the schedule
Developing an updated project schedule
Determining approaches to controlling the project schedule
Implementing agile project management

Learning Outcomes

Estimate the resources required for activities
Estimate the duration for an activity
Determine the earliest start and finish times for activities
Determine the latest start and finish times for activities
Explain and determine total slack

Prepare a project schedule
Identify and explain the critical path
Discuss the project control process
Develop updated schedules based on actual progress and changes
Discuss and apply approaches to control the project schedule
Explain agile project management

Learning Outcomes

After studying this chapter, students should be able to:

Estimate the resources required for activities
Estimate the duration for an activity
Determine the earliest start and finish times for activities
Determine the latest start and finish times for activities
Explain and determine total slack
Prepare a project schedule
Identify and explain the critical path
Discuss the project control process
Develop updated schedules based on actual progress and changes
Discuss and apply approaches to control the project schedule
Explain agile project management

Project Integration Management
Project Resource Management
Project Schedule Management

Project Management Knowledge Areas from PMBOK® Guide

Concepts in this chapter support the following Project Management Knowledge Areas of the PMI Guide to the Project Management Body of Knowledge (PMBOK® Guide):

Project Integration Management

Project Resource Management
Project Schedule Management

More than Wind Infrastructure Development in Kenya

Background

Up to 310 megawatts of clean power
€625 million wind farm
Feasibility studies
Transmission route determination
Clean water bore holes for livestock
Construct schools and medical dispensaries

Analysis and Solutions

Robust project planning
Viability
Sustainability
Schedule
Outcomes
Construct road
Relocate village
Construction Oversight
Private – windfarm
Government – transmission

Vignette A: More than Wind Infrastructure Development in Kenya

Expected to produce up to 310 megawatts of clean power to be added to the Kenyan grid, the €625 million wind farm’s schedule included such tasks as the feasibility of the area for the farm, determination of the transmission line route, completion of bore holes to access clean water for livestock, construction of schools and medical dispensaries, and numbers of meetings with stakeholders and subcontractors.

Robust project planning
Examined viability and sustainability to community
The schedule for the LTWP plan was not as simple as secure funding for the PPP, construct the wind farm, build the transmission line, and connect to the grid.
it was determined that a road was needed to be constructed through Marsabit, one of the most impoverished regions of Kenya, and a village would need to be relocated.
The private contractors in the PPP are providing oversight for the construction of the windfarm.
The government agency is providing oversight to the transmission line construction.

“The president of Kenya has been to the project site, and he’s made it clear how important this project is to the country. That support has filtered down through the community and has helped the project to progress.” The project has run smoothly from the start due to planning, relationships with stakeholders, and a well-designed schedule.

Scheduling Terminal 5

Project Overview

Multiple designs were created
More than 20,000 suppliers
Made up of 16 major projects and 147 subprojects with costs from £1 million to £300 million
Each day, 8,000 workers reported and received 250 deliveries

Project Schedule

Think beyond the traditional methods
Constructed the roof structure offsite to test process and schedule
Delivered roof 3 months early and saved £5.5 million
Included systems testing for opening day
Had issues on opening day

Vignette B: Scheduling Terminal 5

T5 at London Heathrow Airport was designed and built to be the home for British Airways domestic and international flights and was projected to provide service for 30 million passengers annually. With plans for 62 aircraft stands, the complex design was positioned on a 260-hectare (2.6 million m2, 1.0 sq mile) site on the western end of Heathrow and was bordered by the northern and southern runways. Concourse A was planned as a four-story terminal building connected to a satellite building, Concourse B, by an underground people mover transit system. The plan also included the placement of a 4,000 space multi-story car parking garage, hotel facilities, and an air traffic control tower. Access to and from T5 included road links to the M25 motorway and an underground railway to the London Underground Piccadilly Line.

The project
Multiple designs were created before final plan submitted to planning commission.
The schedule for the construction was subject to 700 restrictions, including a requirement to divert two rivers for environmental standards.
The more than 20,000 suppliers for the project provided materials for the buildings, rails and tunnels, infrastructure, or systems.
The complete project was made up of 16 major projects and 147 subprojects with costs from £1 million to £300 million.
Each day, 8,000 workers reported to the site and received almost 250 deliveries per hour
Schedule
Think beyond the traditional methods for contracting and project performance.
Roof team constructed the roof structure at a location offsite first to test the process and schedule. The roof was delivered three months early and saved £5.5 million, much more than the £3.5 million to complete the prototype construction
Included systems testing to prepare the people and the processes for opening day.

Even though the Terminal 5 construction project seemingly had been delivered on time and on budget, not every system was ready for functionality upon opening. Finally, 12 days after its initial opening, Terminal 5 began its full flight schedule.

Estimate Activity Resources

Resources include

People, materials, equipment, facilities

Influence on the duration

Availability of the resources

Types of resources

Sufficient quantities of resources for the activity durations

Potential conflicts with other projects may cause

Involve person with expertise in resource estimate

Estimates influence costs

Estimate Activity Resources

It is necessary to estimate the types and quantities of resources that will be required to perform each specific activity in a project.
Resources include people, materials, equipment, facilities, and so forth.
Having this information is essential in estimating how long it will take to perform each activity and the project as a whole.
A number of factors influence the duration of an activity:
Availability of the resources
Types of resources
Sufficient quantities of resources for the durations of the activities
Potential conflicts with other projects that may cause a delay
When estimating the types and quantities of resources required for each specific activity, it is valuable to involve a person who has expertise or experience with the activity.
Estimated activity resources will also be used later for estimating activity costs and determining the project budget.

Estimate Activity Durations

Duration must be the total elapsed time

Time for the work to be done plus any associated waiting time

Estimate Activity Durations

Once the types and quantities of resources are estimated for each activity, estimates can be made for how long it will take to perform the activities.
The estimated duration for each activity must be the total elapsed time—the time for the work to be done plus any associated waiting time.
The figure above depicts the activity estimated duration for varnishing floors.
It is a good practice to have the person who will be responsible for performing a specific activity estimate the duration for that activity.
Builds buy-in from the person and generates commitments
Avoids bias that may be introduced by having one person estimate the durations for all of the activities
It is important to designate an experienced individual to estimate the durations for all the activities for which the organization or subcontractor is responsible in large projects.
Historical data can be used as a guide in estimating the durations of similar activities.
Estimated duration should be aggressive yet realistic.
Inflating estimated durations in anticipation of the project manager negotiating shorter durations is not a good practice.
Throughout the performance of the project, some activities will take longer than their estimated duration, others will take less time than estimated, and a very few may conform to the estimated duration exactly.
At the beginning of the project, it may not be possible to estimate the durations for all activities with a high level of confidence.
The project team can progressively elaborate the estimated durations as more information is becomes available to allow for more accurate estimated durations.

Why is it a good practice to have the person who will be responsible for performing a specific activity estimate the duration for that activity?

Student Discussion

Why is it a good practice to have the person who will be responsible for performing a specific activity estimate the duration for that activity?

Possible responses to Student Discussion

Builds buy-in from the person and generates commitments

Avoids bias that may be introduced by having one person estimate the durations for all of the activities

The designated individual uses experience to estimate the durations

Historical data can be used as a guide

Why is it a good practice to have the person who will be responsible for performing a specific activity estimate the duration for that activity?

As we just discussed, it is a good practice to have the person who will be responsible for performing a specific activity estimate the duration for that activity.

Builds buy-in from the person and generates commitments
Avoids bias that may be introduced by having one person estimate the durations for all of the activities
It is important to designate an experienced individual to estimate the durations for all the activities for which the organization or subcontractor is responsible, especially for large projects.
Historical data can be used as a guide in estimating the durations of similar activities on future projects.

Explain the statement:
The estimated duration should be aggressive yet realistic.

Student Discussion

Explain the statement: The estimated duration should be aggressive yet realistic.

Possible responses to Student Discussion

Durations should not be too short to try to win the contract

Inflated estimated durations is not good practice

Project manager may not be able to negotiate shorter durations

Some activities will take longer and others shorter durations than planned

As the project progresses, level of confidence for accuracy increases

Explain the statement:

The estimated duration should be aggressive yet realistic.

The estimated duration should be aggressive yet realistic means the following:

Inflating estimated durations in anticipation of the project manager negotiating shorter durations is not a good practice.
Throughout the performance of the project, some activities will take longer than their estimated duration, others will be done in less time than their estimated duration, and a few may conform to the estimated duration exactly.
At the beginning of the project, it may not be possible to estimate the durations for all activities with a level of confidence regarding their accuracy. Estimations may need to be refined as a project proceeds.
The project team can progressively elaborate the estimated durations as more information becomes available, to allow for more accurate estimated durations.

Estimate Activity Durations

This figure depicts the network diagram for a consumer market study, with the estimated durations in days for each activity.

What are the realistic estimates for the activities shown?
What happens if an activity is delayed and will be its impact on the project?
What happens if an activity finishes early?

Establish Project Start and Finish Times

Define the overall window for project completion

May not want to commit to a specific date

Project not start until customer has approved the contract

Delay in contract signing may impact project start

Set finish time as number of days from project start

Establish Project Start and Finish Times

It is necessary to select an estimated start time and a required completion time for the overall project. This is important in order to establish a basis from which to calculate a schedule using the estimated durations for the activities.

Define the overall window, or envelope, of time in which the project must be completed.
The contractor may not want to commit to completing the project by a specific date until the customer has approved the contract.
A delay in signing will likely impact the start date of the project.
The finish time should be stated as a number of days from the start of the project.

Develop Project Schedule

Prior activities for schedule development

Estimate duration of each activity

Establish overall window of time for the project

Develop the schedule timetable

Earliest start and finish times based on estimated start date

Latest start and finish times based on required completion date

Develop Project Schedule

Once you have an estimated duration for each activity in the network must determine (based on durations and sequence) whether the project can be realistically finished by the required completion time.

In order to do this, the contractor should estimate the duration of each activity.
He or she should establish an overall window of time for the project.

Develop a project schedule that provides a timetable for each activity and shows:

The earliest times (or dates) at which each activity can start and finish, based on the project estimated start time (or date)
The latest times (or dates) by which each activity must start and finish in order to complete the project by its required completion time (or date)

Earliest Start and Finish Times

Earliest start time (ES)

Earliest time at which a specific activity can begin

Earliest finish time (EF)

Earliest time by which a specific activity can be completed

EF = ES + Estimated Duration

Calculate forward through the network diagram

A. Earliest Start and Finish Times

Earliest start time (ES) is the earliest time at which a specific activity can begin

It is calculated on the basis of the project estimated start time and the estimated durations of preceding activities.

Earliest finish time (EF) is the earliest time by which a specific activity can be completed

It is calculated by adding the activity’s estimated duration to the activity’s earliest start time

EF = ES + Estimated Duration

Calculate forward through the network diagram from the beginning of the project to the end of the project.

Rule 1:

The earliest start time for a specific activity must be the same as or later than the latest of all the earliest finish times of all the activities leading directly into that specific activity.

Rule 1:

The earliest start time for a specific activity must be the same as or later than the latest of all the earliest finish times of all the activities leading directly into that specific activity.

Earliest Start and Finish Times Calculation

Why is the ES for “Dress Rehearsal” 10?

Earliest Start and Finish Time Calculation

This figures depicts the three activities that go into the production of a “Dress Rehearsal” for a play. You will note that “Practice Skit” has an EF of day 5; “Make Costumes” has an EF of day 10; and “Make Props” has an EF of day 4.
“Dress Rehearsal” cannot start until all three of these activities are finished, so the latest of the EFs for these three activities determines the ES for “Dress Rehearsal.”
The latest of the three EFs is day 10—the earliest finish time for “Make Costumes.”
Therefore, “Dress Rehearsal” cannot start any earlier than day 10. That is, its ES must be day 10 or later.
Even though “Practice Skit” and “Make Props” may finish sooner than “Make Costumes,” “Dress Rehearsal” cannot start because the network dependent relationships indicate that all three activities must be finished before “Dress Rehearsal” can start.

“Identify Target Consumers”

Start date = 0
ES = Start date = 0
Duration = 3
EF = 0 + 3 = 3

“Identify Target Consumers”

In the following slides we will see the different activities and forward calculations that go into a consumer market study project.
The project estimated start date is 0 and the duration is three days.
Therefore, the earliest “Identify Target Consumers” can start is time 0, and the earliest it can finish is 3 days later (because its estimated duration is 3 days).

“Develop Draft Questionnaire”

ES = EF Task 1 = 3
Duration = 10
EF = 3 + 10 = 13

“Develop Draft Questionnaire”

When “Identify Target Consumers” is finished on day 3, “Develop Draft Questionnaire” can start. It has an estimated duration of 10 days, so its ES is day 3 and its EF is day 13.

“Pilot-Test Questionnaire”

ES = EF Task 2 = 13
Duration = 20
EF = 13 + 20 = 33

“Pilot-Test Questionnaire”

When “Develop Draft Questionnaire” is finished on day 13, “Pilot-Test Questionnaire” can start. It has an estimated duration of 20 days, so its ES is day 13 and its EF is day 33.

“Review Comments & Finalize Questionnaire”

ES = EF Task 3 = 33
Duration = 5
EF = 33 + 5 = 38

“Review Comments & Finalize Questionnaire”

When “Pilot-Test Questionnaire” is finished on day 33, “Review Comments & Finalize Questionnaire” can start. It has an estimated duration of 5 days, so its ES is day 33 and its EF is day 38.

“Prepare Mailing Labels,” "Print Questionnaire," "Develop Data Analysis Software," and "Develop Software Test Data"

ES = EF Task 4 = 38
Task 5
Duration = 2
EF = 38 + 2 = 40
Task 6
Duration = 10
EF = 38 + 10 = 48
Task 7
Duration = 12
EF = 38 + 12 = 50
Task 8
Duration = 2
EF = 38 + 2 = 40

“Prepare Mailing Labels,” "Print Questionnaire," "Develop Data Analysis Software," and "Develop Software Test Data"

When “Review Comments & Finalize Questionnaire” is finished on day 38, “Prepare Mailing Labels,” "Print Questionnaire," "Develop Data Analysis Software," and "Develop Software Test Data" can all start.
The ES for each activity is 38, but they each have different EFs.
“Prepare Mailing Labels,” has an estimated duration of 2 days, so its EF is day 40.
"Develop Data Analysis Software" has an estimated duration of 10 days, so its EF is day 48.
"Develop Data Analysis Software" has an estimated duration of 12 days, so its EF is day 50.
"Develop Software Test Data" has an estimated duration of 2 days, so its EF is day 40.

“Mail Questionnaire & Get Responses”

Latest of Tasks 5 and 6 = 48
ES = EF Task 6 = 48
Duration = 65
EF = 48 + 65 = 113

“Mail Questionnaire & Get Responses”

When “Prepare Mailing Labels” and "Print Questionnaire" are finished, “Mail Questionnaire & Get Responses” can start.
The later of the two EF times for “Prepare Mailing Labels” and "Print Questionnaire" is 48, therefore this is the ES.
“Mail Questionnaire & Get Responses” has an estimated duration of 65 days, so its ES is day 48 and its EF is day 113.

“Test Software”

Latest of Tasks 7 and 8 = 50
ES = EF Task 7 = 50
Duration = 5
EF = 50 + 5 = 55

“Test Software”

When "Develop Data Analysis Software" and "Develop Software Test Data" are finished, “Test Software” can start.
The later of the two EF times for “Develop Data Analysis Software" and "Develop Software Test Data" is 50.
"Test Software" has an estimated duration of 5 days, so its ES is day 50 and its EF is day 55.

“Input Response Data”

Latest of Tasks 9 and 10 = 113
ES = EF Task 9 = 113
Duration = 7
EF = 113 + 7 = 120

“Input Response Data”

When “Mail Questionnaire & Get Responses” and "Test Software" are finished, “Input Response Data” can start.
The later of the two EF times for “Mail Questionnaire & Get Responses” and "Test Software" is 113.
"Input Response Data" has an estimated duration of 7 days, so its ES is day 113 and its EF is day 120.

“Analyze Results”

ES = EF Task 11 = 120
Duration = 8
EF = 120 + 8 = 128

“Analyze Results”

When “Input Response Data” is finished on day 120, “Analyze Results” can start.
It has an estimated duration of 8 days, so its ES is day 120 and its EF is day 128.

“Prepare Report”

ES = EF Task 12 = 128
Duration = 10
EF = 128 + 10 = 138

Project not complete in required time

“Prepare Report”

When “Analyze Results” is finished on day 128, “Prepare Report” can start.
It has an estimated duration of 10 days, so its ES is day 128 and its EF is day 138.

The required completion time for this entire project is 130 days. 138 days is 8 days beyond the required completion time, therefore the project was not completed in the required time.

Schedule Table ES and EF

This figure depicts the ES and EF times for the consumer market study project we just analyzed, in a schedule table format.

Latest Start and Finish Times

Latest start time (LS)

Latest time by which a specific activity must be started

Latest finish time (LF)

Latest time by which a specific activity must be completed

LS = LF – Estimated Duration

Calculate backward through the network diagram

Latest Start and Finish Times

Latest start time (LS) is the latest time by which a specific activity must be started in order for the entire project to be finished by its required completion time.

It is calculated by subtracting the activity’s estimated duration from the activity’s latest finish time.

Latest finish time (LF) is the latest time by which a specific activity must be completed in order for the entire project to be finished by its required completion time.

It is calculated on the basis of the project required completion time and the estimated durations of succeeding activities.

LS = LF– Estimated Duration

Calculate backward through the network diagram from the end of the project to the beginning of the project.

Rule 2:

The latest finish time for a specific activity must be the same as or earlier than the earliest of all the latest start times of all the activities emerging directly from that specific activity.

Rule 2:

The latest finish time for a specific activity must be the same as or earlier than the earliest of all the latest start times of all the activities emerging directly from that specific activity.

Latest Start and Finish Times Calculation

Why is the LF for “Print Posters & Brochures” 20?

Latest Start and Finish Times Calculation

These figures show two activities that emerge directly from an activity labeled, “Print Posters & Brochures.”

This project is required to be completed by day 30. Therefore, “Distribute Posters” must be started by day 20 because it has an estimated duration of 10 days, and “Mail Brochures” must be started by day 25 because it has an estimated duration of 5 days.
The earlier of these two LSs is day 20. Therefore, the latest that “Print Posters & Brochures” can finish is day 20, so that “Distribute Posters” can start by day 20.

Even though “Mail Brochures” does not have to start until day 25, “Print Posters & Brochures” must finish by day 20, or else the entire project will be delayed.
If “Print Posters & Brochures” does not finish until day 25, then “Distribute Brochures” will not be able to start until day 25.
Because “Distribute Brochures” has an estimated duration of 10 days, it will not finish until day 35, which is 5 days beyond the project required completion time.

“Prepare Report”

Required completion = 130
LF = Complete date = 130
Duration = 10
LS = 130 - 10 = 120

“Prepare Report”

Now let us look at how to set up the backward calculations for the consumer market study project we just analyzed.

The required completion time for the project is 130 working days.
Therefore, the latest that “Prepare Report,” the last activity, can finish is day 130, and the latest that it can start is day 120 because its estimated duration is 10 days.
In order for “Prepare Report” to start on day 120, the latest that “Analyze Results” can finish is day 120. If the LF for “Analyze Results” is day 120, then its LS is day 112 because its estimated duration is 8 days.

“Analyze Results”

LF = LS Task 13 = 120
Duration = 8
LS = 120 - 8 = 112

“Analyze Results”

In order for “Prepare Report” to start on day 120, the latest that “Analyze Results” can finish is day 120.
If the LF for “Analyze Results” is day 120, then its LS is day 112 because its estimated duration is 8 days.
In order for “Analyze Results” to start on day 112, the latest that “Input Response Data” can finish is day 112.

“Input Response Data”

LF = LS Task 12 = 112
Duration = 7
LS = 112 - 7 = 105

“Input Response Data”

If the LF for “Input Response Data” is day 112, then its LS is day 105 because its estimated duration is 7 days.
In order for “Analyze Results” to start on day 112, the latest that “Input Response Data” can finish is day 112.
If the LF for “Input Response Data” is day 112, then its LS is day 105 because its estimated duration is 7 days.

“Test Software” and “Mail Questionnaire & Get Responses”

LF = LS Task 11 = 105
Task 9
Duration = 65
LS = 105 - 65 = 40
Task 10
Duration = 5
LS = 105 - 5 = 100

“Test Software” and “Mail Questionnaire & Get Responses”

In order for “Input Response Data” to start on day 105, the latest that “Mail Questionnaire & Get Responses” and "Test Software" can finish is day 105.
If the LF for “Mail Questionnaire & Get Responses” is day 105, then its LS is day 40 because its estimated duration is 65 days. If the LF for "Test Software"” is day 105, then its LS is day 100 because its estimated duration is 5 days.

"Develop Data Analysis Software" and "Develop Software Test Data"

LF = LS Task 10 = 100
Task 7
Duration = 12
LS = 100 - 12 = 88
Task 8
Duration = 2
LS = 100 - 2 = 98

"Develop Data Analysis Software" and "Develop Software Test Data"

In order for “Test Software” to start on day 100, the latest that "Develop Data Analysis Software" and "Develop Software Test Data" can finish is day 100.
If the LF for “Develop Data Analysis Software” is day 100, then its LS is day 88 because its estimated duration is 12 days.
If the LF for “Develop Software Test Data” is day 100, then its LS is day 98 because its estimated duration is 2 days.

“Prepare Mailing Labels” and "Print Questionnaire”

LF = LS Task 9 = 40
Task 5
Duration = 2
LS = 40 - 2 = 38
Task 6
Duration = 10
LS = 40 - 10 = 30

“Prepare Mailing Labels” and "Print Questionnaire”

In order for “Mail Questionnaire & Get Responses” to start on day 40, the latest that “Prepare Mailing Labels” and "Print Questionnaire" can finish is day 40.
If the LF for “Prepare Mailing Labels” is day 40, then its LS is day 38 because its estimated duration is 2 days.
If the LF for “Print Questionnaire” is day 40, then its LS is day 30 because its estimated duration is 10 days.

“Review Comments & Finalize Questionnaire”

LF = Earliest LS of Tasks 5, 6, 7, and 8 = 30
LF = LS Task 6 = 30
Duration = 5
LS = 30 - 5 = 25

“Review Comments & Finalize Questionnaire”

Look at “Review Comments & Finalize Questionnaire.”
In order for the four activities emerging from this activity to start by their LS times (so that the project can finish by its required completion time of 130 days), “Review Comments & Finalize Questionnaire” must be finished by the earliest LS of all four activities, according to Rule 2.
The earliest of the four LSs is day 30, the latest time by which “Print Questionnaire” must start.
Therefore, the latest that “Review Comments & Finalize Questionnaire” can finish is day 30.
If the LF for “Review Comments & Finalize Questionnaire” is day 30, then its LS is day 25 because its estimated duration is 5 days.

“Pilot-Test Questionnaire”

LF = LS Task 4 = 25
Duration = 20
LS = 25 - 20 = 5

“Pilot-Test Questionnaire”

In order for “Review Comments & Finalize Questionnaire” to start on day 25, the latest that “Pilot-Test Questionnaire” can finish is day 25.
If the LF for “Pilot-Test Questionnaire” is day 25, then its LS is day 5 because its estimated duration is 20 days.

“Develop Draft Questionnaire”

LF = LS Task 3 = 5
Duration = 10
LS = 5 - 10 = -5

“Develop Draft Questionnaire”

In order for “Pilot-Test Questionnaire” to start on day 5, the latest that “Develop Draft Questionnaire” can finish is day 5.
If the LF for “Develop Draft Questionnaire” is day 5, then its LS is day -5 because its estimated duration is10 days.

“Identify Target Consumers”

LF = LS Task 2 = -5
Duration = 3
LS = -5 - 3 = -8
Start date = 0

Project is 8 days late at start

“Identify Target Consumers”

In order for “Develop Draft Questionnaire” to start on day -5, the latest that “Identify Target Consumers” can finish is day -5.
If the LF for “Input Response Data” is day -5, then its LS is day -8 because its estimated duration is 3 days.

Therefore, the consumer market study project must start 8 days earlier than the planned start date in order to finish in the required 130 days.

Schedule Table LS and LF

Here you see a figure that depicts the schedule table with the LS and LF values added.

Total Slack

Sometimes called float

The difference between EF time of last activity and the project required completion time

Negative slack

Lack of slack over the entire project

Amount of time an activity must be accelerated

Positive slack

Maximum amount of time that the activities on a particular path can be delayed without jeopardizing on-time completion

Total Slack

Total slack is sometimes called float.
It is the difference between EF time of last activity and the project required completion time.
Total slack is calculated for each of the activities by finding the difference between the EF time of the activity and the LF of the activity.
You also look at the difference between the ES and LS of the activity.
Negative slack indicates:
A lack of slack over the entire project
The amount of time an activity must be accelerated to complete the project by the required completion time
Positive slack indicates the maximum amount of time that the activities on a particular path can be delayed without jeopardizing completion of the project by the required completion time.
If the total slack is zero, the activities on the path do not need to be accelerated, but cannot be delayed.

How much slack is in this project to put up new wallpaper?

Student Discussion

How much slack is in this project to put up new wallpaper?

Possible responses to Student Discussion

The total completion time is 20 days

The tasks take 15 days (7+5+3)

The project has 5 days of slack

How much slack is in this project to put up new wallpaper?

This figure depicts a project to remove old wallpaper and put up new wallpaper.

The total completion time is 20 days. The tasks take 15 days (7+5+3).

Therefore, the project has 5 days of slack.

Critical Path

Longest path in the overall network diagram
Find which activities have the least amount of slack

Critical Path

The critical path is this longest path in the overall network diagram.
One way to determine which activities make up the critical path is to find which ones have the least amount of slack.

Critical Path Through a Project

This table shows slack values for each activity in the consumer market study project we just analyzed.
Those with -8 as the total slack are the activities on the critical path.

The figure on the bottom of the slide depicts the critical path through the network diagram for the consumer market study project.

Change in Slack for Critical Path

This figure depicts the change in the critical path if the estimated duration of the Mail Questionnaire & Get Responses task is reduced from 65 days to 55 days.

Note that the tasks on the critical path now have a total slack of 2, the least amount slack in the project.

Free Slack

Time a specific activity can be postponed without delaying the ES of its immediate successor activities

Calculation

Find lowest of the values of total slack for all the activities entering into a specific activity

Subtract value from the values of total slack for the other activities also entering into that same activity

Free Slack

Free slack is the amount of time a specific activity can be postponed without delaying the earliest start time of its immediately succeeding activities.

Free slack is calculated by:

Finding the lowest of the values of total slack for all the activities entering into a specific activity
Then subtracting that value from the values of total slack for the other activities also entering into that same activity

Total Slack Compared to Free Slack

Total slack for Activity 7 = 50

Total slack for Activity 8 = 60

Free slack for Activity 8 = 60 – 50 = 10 days

Total Slack compared to Free Slack

Let’s look at an example of free slack.

Activities 7 and 8 are predecessors for Activity 10 in the figure above.
The values of total slack for activities 7 and 8 are 50 and 60 days, respectively.
The lesser of these two values is 50 days.
Therefore, activity 8, “Develop Software Test Data,” has a free slack of 10 days (60 – 50 = 10) and can slip by up to that amount without delaying the earliest start time of activity 10, “Test Software.”

Bar Chart Format

Gantt chart tool for planning and scheduling
Activities on side
Time scale on top or bottom
Estimated duration in bars
Automatically generated in software systems
Can show relationships between activities

Bar Chart Format

A Gantt chart is the name commonly used for the type of bar chart tool employed in planning and scheduling.
As you can see in the Gantt chart on this slide, the activities are listed on the left-hand side and there is a time scale along the bottom or the top.
The estimated duration for each activity is indicated by a bar spanning the period during which the activity is expected to be accomplished.
Gantt charts often also have a column that indicates who is responsible for each task.
This Gantt chart depicts the consumer market study project that we have been analyzing.
You can probably see how this is an easy way to visually represent when activities are scheduled to occur during a project.
A Gantt chart is a traditional bar chart in that it does not graphically display the dependent relationships of activities.
Be sure to create the network diagram and connect the bars in the Gantt chart with arrows to show relationships.
Project management software can automatically generate a time-scaled bar chart from the schedule table that is based on the network diagram.

Project Control Process

Meetings occur regularly
Gather data on actual performance
Record changes
Monitor progress

Project Control Process

Here you see a figure that illustrates the steps in the project control process.

The project control process starts with establishing a baseline plan that shows how the project scope will be accomplished on schedule and within budget.
Once this baseline plan is agreed upon by the customer and the contractor or project team, the project work can be performed.
It is necessary to monitor the progress to ensure that everything is going according to the plan.
The project control process involves regularly gathering data on project performance, comparing actual performance to planned performance, and taking corrective action immediately if actual performance lags behind planned performance.
This process must occur regularly throughout the project.
Establish regular reporting meetings to compare actual to planned progress.
Gather data on actual performance.
Record information on changes to the project scope, schedule, and budget.

The key to effective project control is measuring actual progress and comparing it to planned progress on a timely and regular basis and taking any needed corrective action immediately.
Project management is a proactive approach to controlling a project to ensure that the project objective is accomplished, even when things do not go according to plan.

Effects of Actual Schedule Performance

Part (a) Total slack = +5

Part (b) Total slack = +2

Effects of Actual Schedule Performance

As you probably know from real-life experience, some activities get completed on time, some are finished ahead of schedule, and others are completed later than scheduled.

The actual finish times (AFs) of completed activities will determine the earliest start and earliest finish times for the remaining activities in the network diagram, as well as the total slack.
This figure depicts the planned and actual performance of a project to remove old wallpaper and install new wallpaper.
Part (a) of the figure is a network diagram for a simple project. It shows that the earliest the project can finish is day 15 (the sum of the estimated durations of the three activities, 7 + 5 + 3).
Since the required completion time is day 20, the project has a total slack of +5 days.
Suppose that activity 1, “Remove Old Wallpaper,” is actually finished on day 10, rather than on day 7 as planned, because it turns out to be more difficult than anticipated.
Part (b) of the figure depicts this deviation from the original plan.
The earliest start and finish times for activities 2 and 3 will be 3 days later than on the original schedule.
Because “Remove Old Wallpaper” is actually finished on day 10, the ES for “Patch Walls” will be day 10 and its EF will be day 15.
Following through with the forward calculations, we find that “Put Up New Wallpaper” will have an ES of day 15 and an EF of day 18.
Comparing this new EF of the last activity to the required completion time of day 20, we find a difference of 2 days. The total slack got worse—it changed in a negative direction, from +5 days to +2 days.
This example illustrates how the actual finish times of activities have a ripple effect, altering the remaining activities’ earliest start and finish times and the total slack.

Incorporate Changes into Schedule

Changes may impact the schedule

Initiated by customer or project team

Result from unanticipated occurrence

Early change may have less impact than later change

Manage requested changes

Estimate impact

Obtain customer approval

Revise project plan, schedule, and costs

Incorporate Changes into Schedule

Throughout a project, changes may occur that impact the schedule.

Changes might be initiated by the customer or the project team, or they might be the result of an unanticipated occurrence.
Changes requested early in the project may have less of an impact on schedule and budget than those requested later in the project.
When the customer requests a change, the contractor or project team should estimate the impact on the project schedule and budget and then obtain customer approval before proceeding.
If the customer approves the proposed revisions to the project schedule and budget, then any additional activities, revised estimated durations, and revised estimated resources and associated costs should be incorporated into the project schedule and budget.
With respect to the project schedule, changes can result in the addition or deletion of activities, re-sequencing of activities, changes to estimated durations for specific activities, or a new required completion time for the project.

Update Project Schedule

Generate forecasts for project finish

Use actual finish dates of completed activities

Enter project changes

Update project schedule

Determine if any changes occur in critical path

Update Project Schedule

An updated project schedule should be generated regularly that forecasts whether the project will finish ahead of or behind its required completion time, or on time.

Once data have been collected on the actual finish times of completed activities and the effects of any project changes, an updated project schedule can be calculated.
Earliest start and finish times for the remaining, uncompleted, activities are calculated by working forward through the network.
They are based on the actual finish times of completed activities and the estimated durations of the uncompleted activities.
The latest start and finish times for the uncompleted activities are calculated by working backward through the network.
An important part of updating project schedules is determining if any changes have occurred on the critical path.

How does the schedule change for the updated project?

Student Discussion

How does the schedule change for the updated project?

Take a look at the updated project depicted in this figure.

1. Completed activities:

Activity 1, “Identify Target Consumers,” actually finished on day 2.
Activity 2, “Develop Draft Questionnaire,” actually finished on day 11.
Activity 3, “Pilot-Test Questionnaire,” actually finished on day 30.

2. Project changes:

It was discovered that the database to be used to prepare the mailing labels was not updated. A new database needs to be purchased before the mailing labels can be prepared. This new database was ordered on day 23. It will take 21 days to get it from the supplier.
A preliminary review of comments from the pilot test of the questionnaire indicates that substantial revisions to the questionnaire are required. Therefore, the duration estimate for activity 4 needs to be increased from 5 days to 15 days.

Possible responses to Student Discussion

How does the schedule change for the updated project?

Here you see the updated schedule.

Note that the total slack for the critical path is now –5 days, instead of the +2 days in that was depicted in the baseline schedule.

The anticipated project completion time is now day 135, which is beyond the required completion time of 130 days.

Control Schedule

Schedule Control Steps

Analyze the schedule for needed corrective action

Decide specific corrective actions to be taken

Revise the plan to incorporate corrective actions

Recalculate the schedule to evaluate the effects of the planned corrective actions

Actions

Repeat steps if not acceptable results
Apply efforts to paths with negative slack
Near-term activities
Long estimated durations
Change may shift critical path
Trade-off of costs and scope

Control Schedule

Schedule control involves four steps:

Analyzing the schedule to determine which areas may need corrective action
Deciding what specific corrective actions should be taken
Revising the plan to incorporate the chosen corrective actions
Recalculating the schedule to evaluate the effects of the planned corrective actions

If the planned corrective actions do not result in an acceptable schedule, these steps need to be repeated.
A concentrated effort to accelerate project progress must be applied to the paths with negative slack.
Activities that are near term (that is, that are in progress or to be started in the immediate future)
Activities that have long estimated durations
The amount of slack should determine the priority with which these concentrated efforts are applied.
A change in the estimated duration of any activity on that path will cause a corresponding change in the slack for that path and may shift the critical path.
Eliminating negative slack by reducing durations of activities will involve a trade-off in the form of an increase in costs or a reduction in the scope of the project.

How must this project be changed to finish in 130 days?

Student Discussion

Now that you have analyzed the changes to this project, now think about how this project must be changed in order to finish in the required 130 days.

Again, you see the network diagram that incorporates changes to the activities in the project.

1. Completed activities:

Activity 1, “Identify Target Consumers,” actually finished on day 2.
Activity 2, “Develop Draft Questionnaire,” actually finished on day 11.
Activity 3, “Pilot-Test Questionnaire,” actually finished on day 30.

2. Project changes:

It was discovered that the database to be used to prepare the mailing labels was not updated. A new database needs to be purchased before the mailing labels can be prepared. This new database was ordered on day 23. It will take 21 days to get it from the supplier.
A preliminary review of comments from the pilot test of the questionnaire indicates that substantial revisions to the questionnaire are required. Therefore, the duration estimate for activity 4 needs to be increased from 5 days to 15 days.

Possible responses to Student Discussion

How change project to finish in 130 days?

Here you see the updated schedule.
Note that the total slack for the critical path is now –5 days, instead of the +2 days in that was depicted in the baseline schedule.
The anticipated project completion time is now day 135, which is beyond the required completion time of 130 days.

How would you make changes to this project so that it is completed on time?

Possible responses:

Reduce time for activity 4.
Reduce time for activity 6.
Reduce time for activity 9.

Ask: If we reduce the time to complete activity 9 by 5 days, what is the impact on the number of responses? This task has already been reduced once by 10 days.

Scheduling
for Information Systems Development

Common problems

Failure to identify all user requirements

Failure to identify user requirements properly

Continuing growth of project scope

Underestimating learning curves for new software packages

Incompatible hardware

Logical design flaws

Poor selection of software

Failure to select the best design strategy

Data incompatibility issues

Failure to perform all phases of the SDLC

Scheduling for Information Systems Development

Scheduling the development of an information system is a challenging process.

Scheduling is often done in a haphazard manner, and, as a result, a large number of IS projects are finished much later than originally promised– or never finished at all.

Among the common problems that often push IS development projects beyond their required completion time are:

Failure to identify all user requirements
Failure to identify user requirements properly
Continuing growth of project scope
Underestimating learning curves for new software packages
Incompatible hardware
Logical design flaws
Poor selection of software
Failure to select the best design strategy
Data incompatibility issues
Failure to perform all phases of the SDLC

IS Example: Activities, Predecessors, Durations

This figure depicts a list of activities, immediate predecessors, and estimated durations for the web-based reporting system project.

The project is required to be completed in 50 days, and it needs to be started as soon as possible.

Ask: Do you think the project can be completed in 50 days?

IS Example: ES and EF Times

Here you see the ES and EF times for each activity in the web-based reporting system project.

Ask: Can you explain the different ES and EF values for the activities?

IS Example: LS and LF Times

This figure depicts the LS and LF times for each activity.

Ask: Can you explain the LS and LF values for the activities?

IS Example:
Schedule Table

IS Example: Schedule Table

This table depicts the project schedule table with the calculated total slack values for each activity.

Ask: Take a minute to analyze this. What is the critical path? How can the project be finished in 50 days?

IS Example: Critical Path

This figure provides you with a visual representation of the critical path for the development project.

The team must determine a way to reduce the development time by 9 days, request that the project completion date be extended from 50 to 59 days, or find some compromise.

After extensive discussions with upper management, in which she stressed the importance of developing the system right the first time and not having to rush through some critical phases of the SDLC, Beth convinced her superiors to extend the project completion time to 60 days.

IS Example: Updated Network Diagram

Beth and her team proceeded with the project and completed activities 1 through 6:

Activity 1, “Gather Data,” actually finished on day 4
Activity 2, “Study Feasibility,” actually finished on day 4
Activity 3, “Prepare Problem Definition Report,” actually finished on day 5
Activity 4, “Interview Users,” actually finished on day 10
Activity 5, “Study Existing System,” actually finished on day 15
Activity 6, “Define User Requirements,” actually finished on day 18

They then discovered that, by using some existing software for the database, they could reduce the estimated duration of activity 9, “Processing & Database,” from 10 days to 8 days. The figure above shows the updated network diagram.

IS Example: Updated Schedule Table

Here you see the updated project schedule.

Note that the critical path has now been reduced to zero with the updates and changes.

Project Management Information Systems

Most systems perform scheduling functions

Calculates at click of the mouse

ES, EF, LS, and LF

Total slack

Critical path

Perform control functions

Project Management Information Systems

Almost all project management information systems allow you to perform the scheduling functions identified in this chapter.
Software will also calculate ES, EF, LS, and LF times, total and free slack, and the critical path
It is important, however, for the project manager to understand what these terms are and what the calculations mean
Do not rely on computers too much!
Virtually all project management information systems also allow you to perform the control functions identified in this chapter.
While an activity is in progress or once an activity has been completed, current information can be entered into the system and the software will automatically revise the project schedule.

Agile Project Management

Scrum approach participants

Product owner
Development team
Scrum master

Process includes

Establish and authorize

Define requirements

Conduct daily Scrum meetings

Conduct sprint review meeting

Conduct sprint retrospective meeting

13. Agile Project Management

Agile project management is an approach to reduce product development time while minimizing risk through continuous interaction between the customer and small self-organizing teams that produce increments of working product features in short time iterations while rapidly adapting to changes in requirements.

The roles of the participants involved in the scrum approach include

A product owner, also referred to as the customer representative, is responsible for defining the customer requirements and product features and for ensuring that the development team delivers an end product with the required features.

The development team develops, delivers, and demonstrates working product increments (portions or modules of the overall end product that is being developed) for specific product features or requirements during a fixed timeframe, called a sprint, also referred to as an iteration.

A Scrum master is a facilitator for the Scrum development process during a sprint whose primary job is to take actions to remove or reduce any obstacles, barriers, or constraints that are impeding progress of the development team toward accomplishing their work tasks and that may negatively impact the successful production and demonstration of a deliverable working product increment by the end of the sprint time.

The agile project management process includes

1. Establishing the rationale, description, funding amount, and target completion date for the final end product (deliverable) and authorizing the project.

2. Defining the product requirements and creating an ordered product backlog of prioritized specific requirements and product features.

3. At the beginning of each sprint the product owner and the development team have a sprint planning meeting to select a set of requirements or features from the top of the product backlog that will be released to the team and that can be produced and demonstrated by the team during the fixed timeframe for the sprint cycle.

4. At the start of each day the development team has a daily Scrum meeting, also referred to as the daily standup as these meetings are usually limited to 15 minutes. Each team member is expected to come prepared to state what they did the previous day, what they plan to do today, and any obstacles that are impeding their work.

5. At the end of the sprint, there is a sprint review meeting at which the development team reviews the work that has been accomplished as well as which items were not completed.

6. At the end of the sprint, there is also a sprint retrospective meeting during which the Scrum team, including the product owner, evaluates performance during the sprint regarding what went well and what could be improved in future sprints.

Critical Success Factors

The person who will be responsible for performing the activity should estimate the duration for that activity. This generates commitment from the person.

The estimated duration for an activity must be based on the types and quantities of resources required to perform the activity.

Activity estimated durations should be aggressive yet realistic.

Activities should not be longer in estimated duration than the time intervals at which the actual progress will be reviewed and compared to planned progress.

Project management involves a proactive approach to controlling a project to ensure that the project objective is accomplished even when things do not go according to plan.

Once the project starts, it is important to monitor progress to ensure that everything is going according to plan.

The key to effective project control is measuring actual progress and comparing it to planned progress on a timely and regular basis and taking any needed corrective action immediately.

The key to effective schedule control is to address any paths with negative or deteriorating slack values aggressively as soon as they are identified. A concentrated effort to accelerate project progress must be applied to these paths.

The person who will be responsible for performing the activity should estimate the duration for that activity. This generates commitment from the person.
The estimated duration for an activity must be based on the types and quantities of resources required to perform the activity.
Activity estimated durations should be aggressive yet realistic.
Activities should not be longer in estimated duration than the time intervals at which the actual progress will be reviewed and compared to planned progress.
Project management involves a proactive approach to controlling a project to ensure that the project objective is accomplished even when things do not go according to plan.
Once the project starts, it is important to monitor progress to ensure that everything is going according to plan.
The key to effective project control is measuring actual progress and comparing it to planned progress on a timely and regular basis and taking any needed corrective action immediately.
The key to effective schedule control is to address any paths with negative or deteriorating slack values aggressively as soon as they are identified. A concentrated effort to accelerate project progress must be applied to these paths.

Critical Success Factors (continued)

The amount of negative slack should determine the priority for applying these concentrated efforts.

When attempting to reduce the duration of a path of activities that has negative slack, focus on activities that are near term and on activities that have long estimated durations.

Addressing schedule problems early will minimize the negative impact on scope and budget.

If a project falls too far behind, getting it back on schedule becomes more difficult, and usually requires spending more money or reducing the scope or quality.

If corrective actions are necessary, decisions must be made regarding a trade-off of scope, time, and cost.

A regular reporting period should be established for comparing actual progress to planned progress.

The shorter the reporting period, the better the chances of identifying problems early and taking corrective actions.

During each reporting period, data on actual performance and information on changes to the project scope, schedule, and budget need to be collected in a timely manner and used to calculate an updated schedule and budget.

The amount of negative slack should determine the priority for applying these concentrated efforts.
When attempting to reduce the duration of a path of activities that has negative slack, focus on activities that are near term and on activities that have long estimated durations.
Addressing schedule problems early will minimize the negative impact on scope and budget.
If a project falls too far behind, getting it back on schedule becomes more difficult, and usually requires spending more money or reducing the scope or quality.
If corrective actions are necessary, decisions must be made regarding a trade-off of scope, time, and cost.
A regular reporting period should be established for comparing actual progress to planned progress.
The shorter the reporting period, the better the chances of identifying problems early and taking corrective actions.
During each reporting period, data on actual performance and information on changes to the project scope, schedule, and budget need to be collected in a timely manner and used to calculate an updated schedule and budget.

Summary

The scheduling function depends on the planning function.

The estimated types and quantities of resources required for an activity, together with the availability of those resources, will influence the estimated duration for how long it will take to perform the activity.

The estimated duration for each activity must be the total elapsed time—the time for the work to be done plus any associated waiting time.

The estimate should be aggressive yet realistic.

It may be easier to estimate the durations for near-term activities, but as the project progresses, the project team can progressively elaborate the estimated the durations as more information becomes known to allow for more accurate estimated durations.

A project schedule provides a timetable for each activity and shows the earliest start (ES) and earliest finish (EF) times and the latest start (LS) and latest finish (LF) times for each activity.

The total slack for a particular path of activities through the network is common to and shared among all activities on that path.

The scheduling function depends on the planning function.
The estimated types and quantities of resources required for an activity, together with the availability of those resources, will influence the estimated duration for how long it will take to perform the activity.
The estimated duration for each activity must be the total elapsed time—the time for the work to be done plus any associated waiting time.
The estimate should be aggressive yet realistic.
It may be easier to estimate the durations for near-term activities, but as the project progresses, the project team can progressively elaborate the estimated the durations as more information becomes known to allow for more accurate estimated durations.
A project schedule provides a timetable for each activity and shows the earliest start (ES) and earliest finish (EF) times and the latest start (LS) and latest finish (LF) times for each activity.
The total slack for a particular path of activities through the network is common to and shared among all activities on that path.

Summary (continued)

The critical path is the longest (most time-consuming) path of activities in the network diagram.

The key to effective project control is measuring actual progress and comparing it to planned progress on a timely and regular basis and taking any needed corrective action immediately.

Actual progress—whether faster or slower than planned—will have an effect on the schedule of the remaining, incomplete activities of the project.

Any type of change—whether initiated by the customer, the contractor, the project manager, a team member, or an unanticipated event—will require a modification to the plan in terms of scope, schedule, and/or budget.

Schedule control involves four steps: analyzing the schedule to determine which areas may need corrective action, deciding what specific corrective actions should be taken, revising the plan to incorporate the chosen corrective actions, and recalculating the schedule to evaluate the effects of the planned corrective actions.

One of the most important factors in effective scheduling is estimating activity durations that are as realistic as possible.

The critical path is the longest (most time-consuming) path of activities in the network diagram.
The key to effective project control is measuring actual progress and comparing it to planned progress on a timely and regular basis and taking any needed corrective action immediately.
Actual progress—whether faster or slower than planned—will have an effect on the schedule of the remaining, incomplete activities of the project.
Any type of change—whether initiated by the customer, the contractor, the project manager, a team member, or an unanticipated event—will require a modification to the plan in terms of scope, schedule, and/or budget.
Schedule control involves four steps: analyzing the schedule to determine which areas may need corrective action, deciding what specific corrective actions should be taken, revising the plan to incorporate the chosen corrective actions, and recalculating the schedule to evaluate the effects of the planned corrective actions.
One of the most important factors in effective scheduling is estimating activity durations that are as realistic as possible.

Chapter Questions

Question 1

A schedule is a timetable for a plan

The schedule cannot be established until the plan has been developed.

Why does the scheduling function depend on the planning function?

Which one must be done first? Why?

1. Why does the scheduling function depend on the planning function? Which one must be done first? Why?

A schedule is a timetable for a plan.
It cannot be established until the plan has been developed.

Question 2

The duration estimate for each activity is the total elapsed time for the work to be done, plus any associated waiting time.

An activity’s duration estimate must be based on the quantity of resources expected to be used on the activity. The estimate should be aggressive, yet realistic.

A Beta distribution using most likely, pessimistic, and optimistic times can be used.

Describe what an activity estimated duration is.

How is it determined?

2. Describe what an activity estimated duration is. How is it determined?

The duration estimate for each activity is the total elapsed time for the work to be done, plus any associated waiting time.
An activity’s duration estimate must be based on the quantity of resources expected to be used on the activity. The estimate should be aggressive, yet realistic.
A Beta distribution using most likely, pessimistic, and optimistic times can be helpful when envisioning the big picture of how long activities are going to take.

Question 3

This is helpful in case the start of the project is delayed for some reason, such as an unexpected snowstorm delaying the start of a construction project.

Example:

A project that requires 100 days to complete with a finish date that is dependent upon the work being completed, rather than on a specific date

Why might a contractor prefer to state a project completion time in terms of number of days after the project starts rather than a specific date?

Give some examples of instances when this would be appropriate.

3. Why might a contractor prefer to state a project completion time in terms of number of days after the project starts rather than a specific date? Give some examples of instances when this would be appropriate.

It can be helpful to think about a project in terms of number of days from the start in case the project start is delayed for some reason, such as an unexpected snowstorm delaying the start of a construction project.
Example: A project that requires 100 days to complete with a finish date that is dependent upon the work being completed, rather than on a specific date

Question 4

The task cannot start until its predecessor is finished, which is day 33.

It has a duration of 5, so it will finish on day 38.

Refer to the figure below, Figure 5.4 from the text. Why is the earliest start time for “Review Comments & Finalize Questionnaire” day 33?

Why is the earliest finish time day 38?

4. Refer to the figure below, Figure 5.4 from the text. Why is the earliest start time for “Review Comments & Finalize Questionnaire” day 33? Why is the earliest finish time day 38?

The task cannot start until its predecessor is finished, which is day 33.
The task has a duration of 5, so it will finish on day 38.

Question 5

Because its predecessor’s latest start time is day 105, it must finish by day 105.

It has a duration of 65, so it must start by day 40

Refer to the figure below, Figure 5.7. Why is the latest start time for “Mail Questionnaires & Get Responses” day 40?

Why is the latest finish time day 105?

5. Refer to the figure below, Figure 5.7. Why is the latest start time for “Mail Questionnaires & Get Responses” day 40? Why is the latest finish time day 105?

Because its predecessor’s latest start time is day 105, the task must finish by day 105.
It has a duration of 65, so it must start by day 40.

Question 6

Total Slack is the amount of time an activity’s earliest finish time can be delayed without delaying succeeding tasks beyond their latest finish times.

If it is positive, you have extra time that can be used if needed.

If it is negative, the activity needs to be completed by its latest finish time or the project completion will be delayed.

Slack = LF – EF or Slack = LS – ES

Free Slack is calculated by finding the lowest of the values of total slack for all the activities entering into a specific activity, and then subtracting it from the values of total slack for the other activities also entering into that same activity.

Describe the different types of project slack.

How is each calculated?

6. Describe the different types of project slack. How is each calculated?

Total Slack is the amount of time an activity’s earliest finish time can be delayed without delaying succeeding tasks beyond their latest finish times.

If it is positive, you have extra time that can be used if needed.
If it is negative, the activity needs to be completed by its latest finish time or the project completion will be delayed.
Slack = LF – EF or Slack = LS – ES
Free Slack is calculated by finding the lowest of the values of total slack for all the activities entering into a specific activity, and then subtracting it from the values of total slack for the other activities also entering into that same activity.

Note: A numbering change happened in the printing of the first run of the seventh edition. Question 7 was moved to be part of Question 6 and Question 9 was split to be questions 8 & 9.

Question 7

If any activity on the critical path is delayed, the whole project will be delayed, so it is important to know what the critical path is.

If any of these activities are accelerated, the project completion date will also be accelerated.

Why is it important to determine the critical path of a project?

What happens if activities on this path are delayed?

What happens if activities on this path are accelerated?

7. Why is it important to determine the critical path of a project? What happens if activities on this path are delayed? What happens if activities on this path are accelerated?

If any activity on the critical path is delayed, the whole project will be delayed, so it is important to know what the critical path is.
If any of these activities are accelerated, the project completion date will also be accelerated.

Note: A numbering change happened in the printing of the first run of the seventh edition. Question 7 was moved to be part of Question 6 and Question 9 was split to be questions 8 & 9.

Question 8

Answers should include setting a baseline for the project plan and monitoring and controlling the actual project progress.

From your experience, describe how you have used a project control process.

If you did not use continual monitoring of the progress, how would this have helped improve the project’s success?

8. From your experience, describe how you have used a project control process. If you did not use continual monitoring of the progress, how would this have helped improve the project’s success?

Specific answers will vary. Students’ answers should include setting a baseline for the project plan and monitoring and controlling the actual project progress.

Note: A numbering change happened in the printing of the first run of the seventh edition. Question 7 was moved to be part of Question 6 and Question 9 was split to be questions 8 & 9.

Question 9

A regular reporting period should be established so that actual progress can be compared to planned progress and any discrepancies can be dealt with as early as possible. The period depends on the complexity or duration of the project.

It may be daily, weekly, bi-weekly, or monthly.

Two kinds of data need to be collected:

Data on actual performance. This includes the actual time that activities were started and/or finished and the actual costs expended and committed.

Information on any changes to the project scope, schedule, and budget.

Why should a project have a regular reporting period? Should all projects have the same reporting period? Why or why not?

What types of data should be collected during each reporting period?

9. Why should a project have a regular reporting period? Should all projects have the same reporting period? Why or why not? What types of data should be collected during each reporting period?

A regular reporting period should be established so that actual progress can be compared to planned progress and any discrepancies can be dealt with as early as possible. The period depends on the complexity or duration of the project. It may be daily, weekly, bi-weekly, or monthly.
Two kinds of data need to be collected:
Data on actual performance
This includes the actual time that activities were started and/or finished and the actual costs expended and committed
Information on any changes to the project scope, schedule, and budget

Note: A numbering change happened in the printing of the first run of the seventh edition. Question 7 was moved to be part of Question 6 and Question 9 was split to be questions 8 & 9.

Question 10

Changes might be initiated by the customer or the project team, or they might be the result of an unanticipated occurrence.

A change might be initiated in order to add an activity, eliminate an activity or modify some aspect of an activity.

Changes can occur at any time throughout the project

If they are requested early in the project, they may have less impact on cost and schedule.

Answers for how the network diagram and schedule are updated should include a recalculation of ES, EF, LS, and LF for the project.

Who can initiate changes to a project schedule?

Describe why and when changes would occur in a project.

How are the network diagram and schedule updated to reflect the changes?

10. Who can initiate changes to a project schedule? Describe why and when changes would occur in a project. How are the network diagram and schedule updated to reflect the changes?

Changes might be initiated by the customer or the project team, or they might be the result of an unanticipated occurrence.
A change might be initiated in order to add an activity, eliminate an activity or modify some aspect of an activity.
Changes can occur at any time throughout the project.
If they are requested early in the project, they may have less impact on cost and schedule.
Specific examples will vary for describing why and when changes would occur in a project.
Answers for how the network diagram and schedule are updated should include a recalculation of ES, EF, LS, and LF for the project.

Question 11

Schedule control involves four steps:

1. Analyzing the schedule to determine which areas may need corrective action

2. Deciding what specific corrective actions should be taken

3. Revising the plan to incorporate the chosen corrective actions

4. Recalculating the schedule to evaluate the effects of the planned corrective actions

Specific examples will vary. Answers will depend upon the project example. Accelerate near-term and longer-duration activities that are on the critical path.

Describe how you would apply the four steps of schedule control to a project.

If the project needs to be accelerated, what kinds of activities would be the primary focus? Why?

11. Describe how you would apply the four steps of schedule control to a project. If the project needs to be accelerated, what kinds of activities would be the primary focus? Why?

Schedule control involves four steps:
Analyzing the schedule to determine which areas may need corrective action
Deciding what specific corrective actions should be taken
Revising the plan to incorporate the chosen corrective actions
Recalculating the schedule to evaluate the effects of the planned corrective actions
Specific examples will vary. Answers will depend upon the project example. Accelerate near-term and longer-duration activities that are on the critical path.

Question 12

Scheduling for IS is often done in a haphazard manner, and thus a large percentage of IS projects are finished much later than originally promised— or never finished at all. One of the most important factors in effective scheduling is arriving at activity duration estimates that are as realistic as possible.

Among the common problems that often push IS development projects beyond their required completion time are the following:

Failure to identify all user requirements

Failure to properly identify user requirements

Continuing growth of project scope

Underestimating learning curves for new software packages

Incompatible hardware

Logical design flaws

Poor selection of software

Failure to select the best design strategy

Data incompatibility issues

Failure to perform all phases of the SDLC

Why is the scheduling of IS projects so challenging?

What are some of the common problems that push IS projects beyond their due dates?

12. Why is the scheduling of IS projects so challenging? What are some of the common problems that push IS projects beyond their due dates?

Scheduling for IS is often done in a haphazard manner, and thus a large percentage of IS projects are finished much later than originally promised— or never finished at all. One of the most important factors in effective scheduling is arriving at activity duration estimates that are as realistic as possible.
Among the common problems that often push IS development projects beyond their required completion time are the following:
Failure to identify all user requirements
Failure to properly identify user requirements
Continuing growth of project scope
Underestimating learning curves for new software packages
Incompatible hardware
Logical design flaws
Poor selection of software
Failure to select the best design strategy
Data incompatibility issues
Failure to perform all phases of the SDLC

Question 13

The longest path in the network is: A – B – E – G – H.

Yes, the project can be completed within 40 weeks. With the current estimates, it will take 36 weeks.

With the changes, the project can still be completed within 40 weeks.

The expected completion has slipped from 36 to 38 weeks. If there is a need to speed it back up, attention should be given to Activity F.

Calculate the ES, EF, LS, and LF times and the slack for each activity in the figure below and identify the critical path for the project.

Can the project be completed in 40 weeks?

Assume that activity A actually finished at 3 weeks; activity B actually finished at 12 weeks; and activity C actually finished at 13 weeks. Recalculate the expected project completion time. Which activities would you focus on in order to get the project back on schedule?

13. Calculate the ES, EF, LS, and LF times and the slack for each activity in the figure below and identify the critical path for the project. Can the project be completed in 40 weeks? Assume that activity A actually finished at 3 weeks; activity B actually finished at 12 weeks; and activity C actually finished at 13 weeks. Recalculate the expected project completion time. Which activities would you focus on in order to get the project back on schedule?

(See the figure on the slide above)

The longest path in the network is: A-B-E-G-H.
Yes, the project can be completed within 40 weeks. With the current estimates, it will take 36 weeks.
With the changes, the project can still be completed within 40 weeks.
However, the expected completion has slipped from 36 to 38 weeks. If there is a need to speed it back up, attention should be given to Activity F.

Question 13

Schedule table for Question 13

Activity	ED	ES	EF	LS	LF	TS
A	2	0	2	4	6	4
B	10	2	12	6	16	4
C	8	2	10	7	15	5
D	15	2	17	8	23	6
E	7	12	19	16	23	4
F	20	10	30	15	35	5
G	12	19	31	23	35	4
H	5	31	36	35	40	4

13. Calculate the ES, EF, LS, and LF times and the slack for each activity in the figure below and identify the critical path for the project. Can the project be completed in 40 weeks? Assume that activity A actually finished at 3 weeks, activity B actually finished at 12 weeks, and activity C actually finished at 13 weeks. Recalculate the expected project completion time. Which activities would you focus on in order to get the project back on schedule?

Here is the schedule table for Question 13 from the previous slide.

Question 13

Schedule table for Question 13

Activity	ED	ES	EF	LS	LF	TS	AF
A	2	3
B	10	12
C	8	13
D	15	3	18	8	23	5
E	7	12	19	16	23	4
F	20	13	33	15	35	2
G	12	19	31	23	35	4
H	5	33	38	35	40	2

13. Calculate the ES, EF, LS, and LF times and the slack for each activity in the figure below and identify the critical path for the project. Can the project be completed in 40 weeks? Assume that activity A actually finished at 3 weeks, activity B actually finished at 12 weeks, and activity C actually finished at 13 weeks. Recalculate the expected project completion time. Which activities would you focus on in order to get the project back on schedule?

Here is the schedule table for Question 13, after the proposed changes in activity finish times are make.

Question 14

The critical path is:

1-2-4-7-8-9.

No, this project cannot be completed within 30 weeks. With the current estimates, it will take 35 weeks.

The project has slipped even further. With the current estimates, it will take 36 weeks. Attention should be given to all activities since they all have negative slack. However, the path 6-8-9 is the most critical.

Calculate the ES, EF, LS, and LF times and the slack for each activity in the figure below, and identify the critical path for the project.

Can the project be completed in 30 weeks?

Assume that “Systems Analysis” actually finished at 8 weeks, “Design Input & Output” actually finished at 15 weeks, and “Design Database” actually finished at 19 weeks. Recalculate the expected project completion time. Which activities would you focus on in order to get the project back on schedule?

14. Calculate the ES, EF, LS, and LF times and the slack for each activity in the figure below, and identify the critical path for the project. Can the project be completed in 30 weeks? Assume that “Systems Analysis” actually finished at 8 weeks, “Design Input & Output” actually finished at 15 weeks, and “Design Database” actually finished at 19 weeks. Recalculate the expected project completion time. Which activities would you focus on in order to get the project back on schedule?

The critical path is: 1-2-4-7-8-9.
No, this project cannot be completed within 30 weeks. With the current estimates, it will take 35 weeks.
The project has slipped even further. With the current estimates, it will take 36 weeks. Attention should be given to all activities since they all have negative slack. However, the path 6-8-9 is the most critical.

Question 14

Schedule table for Question 14

Activity	ED	ES	EF	LS	LF	TS
1. Prob. Def.	2	0	2	-5	-3	-5
2. Sys. Analysis	5	2	7	-3	2	-5
3. Design I/O	3	7	10	6	9	-1
4. Design DB	15	7	22	2	17	-5
5. Develop Input	8	10	18	11	19	1
6. Develop Output	10	10	20	9	19	-1
7. Develop DB	2	22	24	17	19	-5
8. Test System	6	24	30	19	25	-5
9. Implement	5	30	35	25	30	-5

(Here is the schedule table for Question 14 from the previous slide)

Question 14

Schedule table for Question 14

Activity	ED	ES	EF	LS	LF	TS	AF
1. Prob. Def.	2
2. Sys. Analysis	5	8
3. Design I/O	3	15
4. Design DB	15	19
5. Dev. Input	8	15	23	11	19	-4
6. Dev. Output	10	15	25	9	19	-6
7. Dev. DB	2	19	21	17	19	-2
8. Test System	6	25	31	19	25	-6
9. Implement	5	31	36	25	30	-6

(Here is the schedule table, reflecting the changes from part 3 of Question 14)

Question 15

The most critical path in the network is:

B – D – F – G – H – J

No, this project cannot be completed within 30 weeks. With the current estimates, it will take 32 weeks.

The project is still 2 weeks behind the scheduled completion date. Attention should be given to activities

D – F – G – H – J.

Calculate the ES, EF, LS, and LF times and the slack for each activity in the figure below, and identify the critical path for the project.

Can the project be completed in 30 weeks?

Assume that activity A actually finished at 5 weeks and activity B actually finished at 5 weeks. Recalculate the expected project completion time. Which activities would you focus on in order to get the project back on schedule?

15. Calculate the ES, EF, LS, and LF times and the slack for each activity in the figure below, and identify the critical path for the project. Can the project be completed in 30 weeks? Assume that activity A actually finished at 5 weeks and activity B actually finished at 5 weeks. Recalculate the expected project completion time. Which activities would you focus on in order to get the project back on schedule?

The most critical path in the network is: B – D – F – G – H – J.
No, this project cannot be completed within 30 weeks. With the current estimates, it will take 32 weeks.
Even with the changes in finish time, the project is still 2 weeks behind the scheduled completion date. Attention should be given to activities D – F – G – H – J.

Question 15

Schedule table for Question 15

Activity	ED	ES	EF	LS	LF	TS
A	3	0	3	2	5	2
B	5	0	5	-2	3	-2
C	18	3	21	5	23	2
D	7	5	12	3	10	-2
E	10	5	15	5	15	0
F	5	12	17	10	15	-2
G	8	17	25	15	23	-2
H	2	25	27	23	25	-2
I	9	17	26	16	25	-1
J	5	27	32	25	30	-2

(Here is the schedule table for Question 15 from the previous slide)

Question 15

Schedule table for Question 15

Activity	ED	ES	EF	LS	LF	TS	AF
A	3	5
B	5	5
C	18	5	23	5	23	0
D	7	5	12	3	10	-2
E	10	5	15	5	15	0
F	5	12	17	10	15	-2
G	8	17	25	15	23	-2
H	2	25	27	23	25	-2
I	9	17	26	16	25	-1
J	5	27	32	25	30	-2

(Here is the schedule table from part 3 of Question 15)

Project Schedule, Tools, Control
Mind Tools ™

Internet Exercises

Assign the Internet Exercises to your students as homework or complete them together in a computer lab.

Internet Exercises

Sites found contain definitions and recommendations for project schedules, tools, and how to control projects.

Mind Tools™ is a project management resource that helps managers at all levels to improve their performance by reviewing the knowledge base of materials provided and using the methods and tools presented. Mind Tool™ contains links to articles, white papers, methods, tools, templates, events, forums, books, and a glossary.

Videos are available to communicate about project management tools and processes.

Using your favorite Web search engine, perform a search for project schedule, tools , and control and describe what you found.

Visit the MindTools ™ website.

Explore the site.

Click on the “What’s New?” link.

Click on the “Toolkit” link.

Click on the “Newsletter Archive” link.

Internet Exercises

Assign the Internet Exercises to your students as homework or complete them together in a computer lab.

1. Search the web for project schedule. Describe at least three sites that you find. Search with additional terms such as tools and control. List the terms that you have added and describe at least three sites that you find. Here’s a link to Google.

2. For exercises 2 through 5, visit the website for Mind Tools ™ . Explore the site. What information does it provide?

Mid Tools™ is a project management resource that helps managers at all levels to improve their performance by reviewing the knowledge base of materials provided and using the methods and tools presented. Mind Tools™ contains links to articles, white papers, methods, tools, templates, events, forums, books, and a glossary.

3. Click on the link for "What’s New" and describe what you find.

What’s New are categorized by topics such as project planning, scheduling, and Microsoft Project.

4. Click on the "Toolkit" link. Read through a topic that interests you. Provide a one-page summary..

5. Explore the “Newsletter Archives” and click on the “Newsletter Sign Up” link to subscribe to the free newsletter. In addition, under the “More Resources” link, click on “Videos,” read an article and watch a video that interests you and provide a one-page summary...

A number of methods and tools are available to guide project managers through a collection of essential project management skills, methods, tools, and competencies that help improve the probability of project success. As with many sites on the Internet, websites are dynamic and change. The links provided might have changed since the creation of the document.

A Not-For-Profit Medical Research Center

Case Study 1

Case Study #1: A Not-For-Profit Medical Research Center

This case continues through to chapter 8. Each chapter has questions to reinforce the concepts presented. Have students save their work for this case study for the work they will do in chapters 6 to 8.
This is an open-ended case study, so encourage students to use their creativity.
As the director of external affairs for a national not-for-profit medical research center you are tasked with producing a shorter, simpler, easy-to-read annual report to show the benefits of the center's research and the impact on people's lives in an effort to help raise funds for the center.

Group Activity

Form groups of three to five members. Have each group perform the assigned tasks. Allow each group to present their answers.

Case Study 1
Question 1

Responses should use the list of tasks developed in chapter 4 and include the estimated duration for each task.

Develop an estimated duration for each activity.

1. Develop an estimated duration for each activity.

Responses should use the list of tasks developed in chapter 4 and include the estimated duration for each task.

Case Study 1
Question 2

Responses could be presented in a network diagram or in the schedule table format.

The project should finish in 180 days.

If the original plan is not completed by 180 days, the responses should describe what tasks were revised to meet the required completion date.

Using a project start time of 0 (or May 15) and a required project completion time of 180 days (or November 15), calculate the ES, EF, LS, and LF times and total slack for each activity.

If your calculations result in a project schedule with negative total slack, revise the project scope, activity estimated durations, and/or sequence or dependent relationships among activities to arrive at an acceptable baseline schedule for completing the project within 180 days (or by November 15). Describe the revisions you made.

2. Using a project start time of 0 (or May 15) and a required project completion time of 180 days (or November 15), calculate the ES, EF, LS, and LF times and total slack for each activity. If your calculations result in a project schedule with negative total slack, revise the project scope, activity estimated durations, and/or sequence or dependent relationships among activities to arrive at an acceptable baseline schedule for completing the project within 180 days (or by November 15). Describe the revisions you made.

Responses could be presented in a network diagram or in the schedule table format– either would be correct.
The project should finish in 180 days.
If the original plan is not completed by 180 days, the responses should describe what tasks were revised to meet the required completion date.

Case Study 1
Question 3

Responses can be presented in a list of activity names, highlighted in the network diagram, or highlighted in the schedule table.

Determine the critical path and identify the activities that make up the critical path.

3. Determine the critical path and identify the activities that make up the critical path.

Responses can be presented in a list of activity names, highlighted in the network diagram, or highlighted in the schedule table.

Case Study 1
Question 4

The bar chart can be drawn or produced using a project management information system like Microsoft Project.

Include arrows to show the dependencies of the bars.

Produce a bar chart (Gantt Chart) based on the ES and EF times from the schedule in item 2.

4. Produce a bar chart (Gantt Chart) based on the ES and EF times from the schedule in item 2.

The bar chart can be drawn or produced using a project management information system like Microsoft Project.
Suggest that students might want to include arrows to show the dependencies of the bars.

The Wedding

Case Study 2

Case Study #2: The Wedding

This case continues through to chapter 8. Each chapter has questions to reinforce the concepts presented. Have students save their work for this case study for the work they will do in chapters 6 to 8.
This is an open-ended case study. The students have the opportunity to be very creative on this one. Encourage that creativity.
Tony and Peggy Sue want to get married and have family that want to plan the wedding for them without considering what Tony or Peggy Sue would want.

Group Activity

Form groups of three to five members. Have each group perform their assigned tasks. Allow each group to present their answers.

Case Study 2
Question 1

Responses should use the list of tasks developed in chapter 4 and include the estimated duration for each task.

Develop an estimated duration for each activity.

1. Develop an estimated duration for each activity.

Responses should use the list of tasks developed in chapter 4 and include the estimated duration for each task.

Case Study 2
Question 2

Responses could be presented in a network diagram or in the schedule table format. The project should finish in 180 days.

If the original plan is not completed by 180 days, the responses should describe what tasks were revised to meet the required completion date.

Using a project start time of 0 (or January 1) and a required project completion time of 180 days (or June 30), calculate the ES, EF, LS, and LF times and total slack for each activity.

2. Using a project start time of 0 (or January 1) and a required project completion time of 180 days (or June 30), calculate the ES, EF, LS, and LF times and total slack for each activity. If your calculations result in a project schedule with negative total slack, revise the project scope, activity estimated durations, and/or sequence or dependent relationships among activities to arrive at an acceptable baseline schedule for completing the project within 180 days (or by June 30). Describe the revisions you made.

Responses could be presented in a network diagram or in the schedule table format.
The project should finish in 180 days.
If the original plan is not completed by 180 days, the responses should describe what tasks were revised to meet the required completion date.

Case Study 2
Question 3

Responses can be presented in a list of activity names, highlighted in the network diagram, or highlighted in the schedule table.

Determine the critical path and identify the activities that make up the critical path.

3. Determine the critical path and identify the activities that make up the critical path.

Responses can be presented in a list of activity names, highlighted in the network diagram, or highlighted in the schedule table.

Case Study 2
Question 4

The bar chart can be drawn or produced using a project management information system like Microsoft Project.

Include arrows to show the dependencies of the bars.

Produce a bar chart (Gantt Chart) based on the ES and EF times from the schedule in item 2.

4. Produce a bar chart (Gantt Chart) based on the ES and EF times from the schedule in item 2.

The bar chart can be drawn or produced using a project management information system like Microsoft Project.
Suggest that students include arrows to show the dependencies of the bars.

Probabilistic Activity Durations

Appendix

Activity Duration Estimates

Used when high degree uncertainty for duration

Optimistic time (to)

Time completed if everything goes perfectly well

Most likely time (tm)

Time completed under normal conditions

Pessimistic time (tp)

Time completed under adverse circumstances

Activity Duration Estimates

With projects for which there is a high degree of uncertainty about the activity duration estimates, it is possible to use three estimates for each activity:

Optimistic time (to) is the time in which a particular activity can be completed if everything goes perfectly well.
Most likely time (tm) is the time in which a particular activity is completed under normal conditions.
Pessimistic time (tp) is the time in which a particular activity can be completed under adverse circumstances.

Establishing these three time estimates makes it possible to take uncertainty into account when estimating how long an activity will take.

The Beta Probability Distribution

te = (to + 4(tm) + tp)/6

Example: te = (1 + 4(5) + 15)/6 = 6 weeks

The Beta Probability Distribution

In network planning, when three time estimates are used for each activity, it is assumed that the three estimates follow a beta probability distribution.

The expected duration is calculated using the following formula: te = (to + 4(tm) + tp)/6

Assume that the optimistic time for an activity is 1 week, the most likely time is 5 weeks, and the pessimistic time is 15 weeks. The expected duration for this activity is te = (1 + 4(5) + 15)/6 = 6 weeks

The figure above depicts the beta probability distribution.

Probability Fundamentals

Stochastic, or probabilistic, technique

Uses the three time estimates

Allows for uncertainty

Deterministic technique

Uses one time estimate

Central limit theorem of probability

Beta probability distribution variance

Variance = s2 = ((tp – to)/6)2

Standard deviation = square root of variance

Probability Fundamentals

Network planning in which three time estimates are used for each activity can be considered a stochastic, or probabilistic, technique, since these calculations allow for uncertainty.
Any technique that uses only one time estimate is considered to be a deterministic technique. If only one time estimate is used for each activity, probability calculations cannot be made.
The central limit theorem of probability theory states that the total probability distribution is not a beta probability distribution, but a normal probability distribution.
The variance for the beta probability distribution of an activity is found with the following formula: Variance = s2 = ((tp – to)/6)2
Note that the variance of the normal distribution is the sum of the variances of the beta distribution.
The standard deviation, s, is another measure of the dispersion of a distribution and is equal to the square root of the variance.
The total probability distribution of all the activities on the critical path of a network diagram is a normal distribution, with a mean equal to the sum of the individual activity expected durations and a variance equal to the sum of the individual activity variances.
Review the example presented in the book. Especially refer to figures 5.28 and 5.29.

Normal Probability Distribution

Here one sees an illustration of the normal probably distribution.

Example Project

Here is an example of how you can calculate the variance for three different activities, using the formula for finding variance te = (to + 4(tm) + tp)/6.

The rectangle below each activity shows the optimistic, most likely and pessimistic completion times.

Example Project: Probability Distribution

Here you can see graphical representations of the variance for each activity A, B, and C, as well as the total.

te = (to + 4(tm) + tp)/6

te = (20 + 4(35) + 56) / 6 = 36 days

Example Project: Probable Finish Times

Variance = s2 = ((tp – to)/6)2

Standard deviation = square root of variance

• There is a 99 percent chance (0.99 probability) of completing the project in 23.76 to 48.24 days.

• There is a 95 percent chance (0.95 probability) of completing the project in 27.84 to 44.16 days.

• There is a 47.5 percent chance (0.475 probability) of completing the project in 27.84 to 36 days.

• There is a 47.5 percent chance (0.475 probability) of completing the project in 36 to 44.16 days.

• There is a 68 percent chance (0.68 probability) of completing the project in 31.92 to 40.08 days.

• There is a 34 percent chance (0.34 probability) of completing the project in 31.92 to 36 days.

• There is a 34 percent chance (0.34 probability) of completing the project in 36 to 40.08 days.

• There is a 13.5 percent chance (0.135 probability) of completing the project in 27.84 to 31.92 days.

• There is a 13.5 percent chance (0.135 probability) of completing the project in 40.08 to 44.16 days.

• There is a 0.5 percent chance (0.005 probability) of completing the project before 23.76 days.

• There is a 0.5 percent chance (0.005 probability) of completing the project after 48.24 days.

Calculating Probability

Z = (LF – EF)/st

LF = required completion time for the project

EF = earliest expected finish time for the project (mean of the normal distribution)

st = standard deviation of the total distribution of the activities on the longest (or slowest) path leading to project completion

Z = number of standard deviations between EF and LF on the normal probability curve

Calculating Probability

In order to find the probability of actually completing a project before its required completion time, the following formula is used: Z = (LF – EF)/st

The elements in this formula are as follows:

LF (latest finish) is the required completion time for the project.
EF is the earliest expected finish time for the project, which is determined by finding the mean of the normal distribution.
st is the standard deviation of the total distribution of the activities on the longest (or slowest) path leading to project completion.
In the above equation, Z measures the number of standard deviations between EF and LF on the normal probability curve.
Review the example presented in the book, particularly the example begun in Figure 5.28. Use Table 5.1 to determine the percent chance for the Z calculated for the example.

Example Project: Probability Distribution

Use Table 5.1 to determine percent chance to finish within the 42 days required

Z = (LF – EF)/st = (42 – 36)/4.08 = 1.47

Probability = 0.50000 + 0.42922 = 0.92922

Example Project: Probability Distribution

Review the example presented in the book. This is the example begun in Figure 5.28. Use Table 5.1 to determine the percent chance for the Z calculated for the example.

To determine percent chance to finish within the 42 days required, use the formula we just learned.
Z = (LF – EF)/st = (42 – 36)/4.08 = 1.47
Probability = 0.50000 + 0.42922 = 0.92922
There is a 92.9% chance of the project finishing within 42 days.

Probabilistic Activity Durations

Questions

Probabilistic Activity Durations Appendix
Question 1

True

te = (to + 4(tm) + tp)/6

True or false:

In order to calculate the probability of finishing a project by its required completion time, it is necessary to have three time estimates for each activity and the required completion time for the project.

1. True or false: In order to calculate the probability of finishing a project by its required completion time, it is necessary to have three time estimates for each activity and the required completion time for the project.

True.
te = (to + 4(tm) + tp)/6

Probabilistic Activity Durations Appendix
Question 2

Expected duration =

[2 + 4(14) + 14] / 6

= 72 / 6

= 12

Variance = [(14 - 2)/6]2 = 4.0

Standard deviation = 2.0

What are the expected duration, variance, and standard deviation for an activity whose three time estimates are

to = 2, tm = 14, and tp = 14?

2. What are the expected duration, variance, and standard deviation for an activity whose three time estimates are to = 2, tm = 14, and tp = 14?

Expected duration = [2 + 4(14) + 14] / 6

= 72 / 6

= 12

Variance = [(14 - 2)/6]2 = 4.0
Standard deviation = 2.0

Probabilistic Activity Durations Appendix
Question 3

The mean is not a measure of dispersion.

Which of the following is not a measure of the dispersion, or spread, of a distribution: variance, mean, or standard deviation?

3. Which of the following is not a measure of the dispersion, or spread, of a distribution: variance, mean, or standard deviation?

The mean is not a measure of dispersion.

Probabilistic Activity Durations Appendix
Question 4

Z = (130 – 138) / 6 = –1.33

Using Table 5.1, the probability of completing the project between 130 and 138 days is 40.824%.

To determine the probability of completing the project before 130 days, you need to subtract 0.40824 from 0.5000. Therefore, there is a 9.176% probability of completing the project by its required completion time of 130 days.

The earliest expected finish time for a project is 138 days, and its required completion time is 130 days.

What is the probability of completing the project before its required time if st (the standard deviation of the total distribution of the activities on the longest path) is 6?

4. The earliest expected finish time for a project is 138 days, and its required completion time is 130 days. What is the probability of completing the project before its required time if st (the standard deviation of the total distribution of the activities on the longest path) is 6?

Z = (130 – 138) / 6 = –1.33
Using Table 5.1, the probability of completing the project between 130 and 138 days is 40.824%.
To determine the probability of completing the project before 130 days, you need to subtract 0.40824 from 0.5000.
Therefore, there is a 9.176% probability of completing the project by its required completion time of 130 days.

Microsoft Project

Appendix

The Appendix in this chapter introduces Microsoft Project. Have the students produce the displays that are shown in the chapter.

Appendix
Microsoft Project

This second appendix activities are

Enter the estimated durations for each task

Examine the project schedule

Produce a Gantt chart

Determine the critical path

Set a baseline to help track the project

Monitor and control the schedule

Edit task information

Produce reports

Most widely used project management software system in the business environment today.

It is powerful, easy to use, and available at a very reasonable price.

A free trial version is on the Microsoft website.

The Gantt Chart View and the Task ribbon are the default view when Microsoft Project is first opened.

Other views are chosen by clicking on the arrow in the View group on the Task ribbon and selecting the name from the drop down list.

In this appendix, we will discuss how Microsoft Project can be used to support the techniques discussed in this chapter based on the consumer market study example. To retrieve your project information, on the File menu, click Open and locate the consumer market study file you saved in Chapter 4.
We are now ready to enter the estimated durations for each task, examine the project schedule, produce a Gantt chart, determine the critical path, set a baseline to help track the project, monitor and control the schedule, edit task information, and produce reports.

Figure 5A.1, Add Duration Data

Figure 5A.1 depicts the duration data for the project. The time can be entered in as m for minutes, h for hours, d for days, w for weeks, or mon for months.
The duration time needs to be to the level that the project task can be monitored and controlled.
The default time duration is days.
The project title in the first row serves as a summary of the total time necessary for the project.

Figure 5A.2, Gantt Chart View/Schedule Table

Figure 5A.2 depicts the schedule table for the project.
Microsoft Project automatically calculates the ES, EF, LS, and LF for the project.
Other tables are available on the Tables menu.
Have the students explore the different types of tables.
The information presented in the tables and the choices of table types are dependent upon the view prior to choosing the table.

Figure 5A.3, Gantt Chart with Critical Path

Figure 5A.3 depicts the Gantt chart with the highlighted critical path in red.
The highlighting of the critical path is important to help show the tasks that, if delayed, would delay the completion of the project.

Figure 5A.4, Critical Tasks Report

Figure 5A.4 depicts the critical task report that shows information about each of the tasks on the critical path.
This is a valuable report for communication with the project team about the tasks on the critical path.

Figure 5A.5, Edit Activity Duration

Figure 5A.5 depicts the change in the schedule of the Mail Questionnaire & Get Responses task from 65 days to 55 days.
This change was made to reduce the project duration.
The total time for the project was 138 days.
The reduction of time for the task from 65 to 55 days reduces the total time to 128 days.

Figure 5A.6, Task Information

Figure 5A.6 depicts the input screen within the General tab in the Task Information window.
The General tab is used to record the task progress.
Entering information about the actual performance of the tasks permits other analysis to be completed on the schedule and costs.

Figure 5A.7, Insert New Manually Scheduled Activity

Figure 5A.7 depicts the insertion of a new manually scheduled activity.
In some projects, the project team defines a new task that needs to be completed for the project.
The new task is entered by clicking on the task name for the row of the task that will be below the new task.
Microsoft Project will automatically adjust the task numbers and the predecessor numbers.

Figure 5A.8, Updated Predecessors

Figure 5A.8 depicts the updated predecessors on the task list after adding a new task. Note that Microsoft Project has automatically adjusted the task numbers and the predecessor numbers.

Figure 5A.9, Tracking Table

Figure 5A.9 depicts the Tracking Table.
The tracking table shows how the project is progressing relative to the baseline that was set.
If the baseline was not set, then Microsoft Project will not have anything to compare for the tracking table calculations.
The percentages display the amount of completion for the tasks and the summary tasks.

Figure 5A.10, Tracking Gantt

Figure 5A.10 depicts the Tracking Gantt.
Each of the bars has two bars.
One is for the baseline plan.
The other is for the actual progress of the project.
This report is good to see the effects of the changes to the project for tasks that are completed early, late, or on-time.

Figure 5A.11, Variance Table

Figure 5A.11 depicts the Variance Table.
The variance table shows the start and finish of each activity and summary task, the baseline start and finish, and the variance of the start and finish.
This variance table is used to evaluate the impact on the completion of the project of changes in the task start dates.

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Teaching Strategies

The first vignette reinforces the need to interact with community members and key stakeholders when planning the schedule. Sometimes part of the solution of the project is the creation of other beneficial projects to help with buy in.
The second vignette reinforces that the first design of a project might not be the final plan. Complex projects require creative solutions to keep all the aspects on track and the project to be completed on time and within budget. Even though it had difficulties and a few failures at the start, the complex project was scheduled well.
Sometimes, when planning the schedule, calculated times are for activity completion are not accurate. This can become a problem when no one takes the time to examine the actual time it takes to complete activities.
Have students plan the amount of time that it would take to travel between two cities that are near campus. After they calculate the time to travel, have them think about how they would factor in extenuating circumstances (like a flat tire, the need to refill the fuel tank, the need to stop for food, or a traffic-blocking accident).
Have students calculate the ES, EF, LS, and LF times in class to be sure they understand what it means to calculate forward and to calculate backward.
The ES, EF, LS, LF times on the network diagram for the consumer market study are included in the chapter materials. Have the students compare the textbook diagram with the schedule table in Microsoft Project.
Have the students report on the similarities and the differences.

Chapter Concepts

This chapter discusses monitoring and controlling the progress of the project, re-planning, and updating the project schedule.
Once a project actually begins, it is necessary to monitor progress to ensure that everything goes according to schedule. This involves measuring actual progress and comparing it to the schedule.
If at any time during the project, it is determined that the project is behind schedule, corrective action must be taken to get back on schedule, which becomes increasingly difficult as a project falls further behind.

Based on the material in this chapter, students will become familiar with:

Estimating the resources required for each activity
Estimating the duration for each activity
Establishing the estimated start time and required completion time for the overall project
Calculating the earliest times at which each activity can start and finish, based on the project estimated start time
Calculating the latest times by which each activity must start and finish in order to complete the project by its required completion time
Determining the amount of positive or negative slack between the time each activity can start or finish and the time it must start or finish
Identifying the critical (longest) path of activities
Performing the steps in the project control process
Determining the effects of actual schedule performance on the project schedule
Incorporating changes into the schedule
Developing an updated project schedule
Determining approaches to controlling the project schedule
Implementing agile project management

Learning Outcomes

After studying this chapter, students should be able to:

Estimate the resources required for activities
Estimate the duration for an activity
Determine the earliest start and finish times for activities
Determine the latest start and finish times for activities
Explain and determine total slack
Prepare a project schedule
Identify and explain the critical path
Discuss the project control process
Develop updated schedules based on actual progress and changes
Discuss and apply approaches to control the project schedule
Explain agile project management

Project Management Knowledge Areas from PMBOK® Guide

Concepts in this chapter support the following Project Management Knowledge Areas of the PMI Guide to the Project Management Body of Knowledge (PMBOK® Guide):

Project Integration Management

Project Resource Management
Project Schedule Management

Vignette A: More than Wind Infrastructure Development in Kenya

Robust project planning
Examined viability and sustainability to community
The schedule for the LTWP plan was not as simple as secure funding for the PPP, construct the wind farm, build the transmission line, and connect to the grid.
it was determined that a road was needed to be constructed through Marsabit, one of the most impoverished regions of Kenya, and a village would need to be relocated.
The private contractors in the PPP are providing oversight for the construction of the windfarm.
The government agency is providing oversight to the transmission line construction.

Vignette B: Scheduling Terminal 5

The project
Multiple designs were created before final plan submitted to planning commission.
The schedule for the construction was subject to 700 restrictions, including a requirement to divert two rivers for environmental standards.
The more than 20,000 suppliers for the project provided materials for the buildings, rails and tunnels, infrastructure, or systems.
The complete project was made up of 16 major projects and 147 subprojects with costs from £1 million to £300 million.
Each day, 8,000 workers reported to the site and received almost 250 deliveries per hour
Schedule
Think beyond the traditional methods for contracting and project performance.
Roof team constructed the roof structure at a location offsite first to test the process and schedule. The roof was delivered three months early and saved £5.5 million, much more than the £3.5 million to complete the prototype construction
Included systems testing to prepare the people and the processes for opening day.

Estimate Activity Resources

It is necessary to estimate the types and quantities of resources that will be required to perform each specific activity in a project.
Resources include people, materials, equipment, facilities, and so forth.
Having this information is essential in estimating how long it will take to perform each activity and the project as a whole.
A number of factors influence the duration of an activity:
Availability of the resources
Types of resources
Sufficient quantities of resources for the durations of the activities
Potential conflicts with other projects that may cause a delay
When estimating the types and quantities of resources required for each specific activity, it is valuable to involve a person who has expertise or experience with the activity.
Estimated activity resources will also be used later for estimating activity costs and determining the project budget.

Estimate Activity Durations

Once the types and quantities of resources are estimated for each activity, estimates can be made for how long it will take to perform the activities.
The estimated duration for each activity must be the total elapsed time—the time for the work to be done plus any associated waiting time.
The figure above depicts the activity estimated duration for varnishing floors.
It is a good practice to have the person who will be responsible for performing a specific activity estimate the duration for that activity.
Builds buy-in from the person and generates commitments
Avoids bias that may be introduced by having one person estimate the durations for all of the activities
It is important to designate an experienced individual to estimate the durations for all the activities for which the organization or subcontractor is responsible in large projects.
Historical data can be used as a guide in estimating the durations of similar activities.
Estimated duration should be aggressive yet realistic.
Inflating estimated durations in anticipation of the project manager negotiating shorter durations is not a good practice.
Throughout the performance of the project, some activities will take longer than their estimated duration, others will take less time than estimated, and a very few may conform to the estimated duration exactly.
At the beginning of the project, it may not be possible to estimate the durations for all activities with a high level of confidence.
The project team can progressively elaborate the estimated durations as more information is becomes available to allow for more accurate estimated durations.

Why is it a good practice to have the person who will be responsible for performing a specific activity estimate the duration for that activity?

As we just discussed, it is a good practice to have the person who will be responsible for performing a specific activity estimate the duration for that activity.

Builds buy-in from the person and generates commitments
Avoids bias that may be introduced by having one person estimate the durations for all of the activities
It is important to designate an experienced individual to estimate the durations for all the activities for which the organization or subcontractor is responsible, especially for large projects.
Historical data can be used as a guide in estimating the durations of similar activities on future projects.

Explain the statement: The estimated duration should be aggressive yet realistic.

The estimated duration should be aggressive yet realistic means the following:

Inflating estimated durations in anticipation of the project manager negotiating shorter durations is not a good practice.
Throughout the performance of the project, some activities will take longer than their estimated duration, others will be done in less time than their estimated duration, and a few may conform to the estimated duration exactly.
At the beginning of the project, it may not be possible to estimate the durations for all activities with a level of confidence regarding their accuracy. Estimations may need to be refined as a project proceeds.
The project team can progressively elaborate the estimated durations as more information becomes available, to allow for more accurate estimated durations.

This figure depicts the network diagram for a consumer market study, with the estimated durations in days for each activity.

What are the realistic estimates for the activities shown?
What happens if an activity is delayed and will be its impact on the project?
What happens if an activity finishes early?

Establish Project Start and Finish Times

Define the overall window, or envelope, of time in which the project must be completed.
The contractor may not want to commit to completing the project by a specific date until the customer has approved the contract.
A delay in signing will likely impact the start date of the project.
The finish time should be stated as a number of days from the start of the project.

Develop Project Schedule

In order to do this, the contractor should estimate the duration of each activity.
He or she should establish an overall window of time for the project.

Develop a project schedule that provides a timetable for each activity and shows:

The earliest times (or dates) at which each activity can start and finish, based on the project estimated start time (or date)
The latest times (or dates) by which each activity must start and finish in order to complete the project by its required completion time (or date)

A. Earliest Start and Finish Times

Earliest start time (ES) is the earliest time at which a specific activity can begin

It is calculated on the basis of the project estimated start time and the estimated durations of preceding activities.

Earliest finish time (EF) is the earliest time by which a specific activity can be completed

It is calculated by adding the activity’s estimated duration to the activity’s earliest start time

EF = ES + Estimated Duration

Calculate forward through the network diagram from the beginning of the project to the end of the project.

Rule 1:

The earliest start time for a specific activity must be the same as or later than the latest of all the earliest finish times of all the activities leading directly into that specific activity.

Earliest Start and Finish Time Calculation

This figures depicts the three activities that go into the production of a “Dress Rehearsal” for a play. You will note that “Practice Skit” has an EF of day 5; “Make Costumes” has an EF of day 10; and “Make Props” has an EF of day 4.
“Dress Rehearsal” cannot start until all three of these activities are finished, so the latest of the EFs for these three activities determines the ES for “Dress Rehearsal.”
The latest of the three EFs is day 10—the earliest finish time for “Make Costumes.”
Therefore, “Dress Rehearsal” cannot start any earlier than day 10. That is, its ES must be day 10 or later.
Even though “Practice Skit” and “Make Props” may finish sooner than “Make Costumes,” “Dress Rehearsal” cannot start because the network dependent relationships indicate that all three activities must be finished before “Dress Rehearsal” can start.

“Identify Target Consumers”

In the following slides we will see the different activities and forward calculations that go into a consumer market study project.
The project estimated start date is 0 and the duration is three days.
Therefore, the earliest “Identify Target Consumers” can start is time 0, and the earliest it can finish is 3 days later (because its estimated duration is 3 days).

“Develop Draft Questionnaire”

When “Identify Target Consumers” is finished on day 3, “Develop Draft Questionnaire” can start. It has an estimated duration of 10 days, so its ES is day 3 and its EF is day 13.

“Pilot-Test Questionnaire”

When “Develop Draft Questionnaire” is finished on day 13, “Pilot-Test Questionnaire” can start. It has an estimated duration of 20 days, so its ES is day 13 and its EF is day 33.

“Review Comments & Finalize Questionnaire”

When “Pilot-Test Questionnaire” is finished on day 33, “Review Comments & Finalize Questionnaire” can start. It has an estimated duration of 5 days, so its ES is day 33 and its EF is day 38.

“Prepare Mailing Labels,” "Print Questionnaire," "Develop Data Analysis Software," and "Develop Software Test Data"

When “Review Comments & Finalize Questionnaire” is finished on day 38, “Prepare Mailing Labels,” "Print Questionnaire," "Develop Data Analysis Software," and "Develop Software Test Data" can all start.
The ES for each activity is 38, but they each have different EFs.
“Prepare Mailing Labels,” has an estimated duration of 2 days, so its EF is day 40.
"Develop Data Analysis Software" has an estimated duration of 10 days, so its EF is day 48.
"Develop Data Analysis Software" has an estimated duration of 12 days, so its EF is day 50.
"Develop Software Test Data" has an estimated duration of 2 days, so its EF is day 40.

“Mail Questionnaire & Get Responses”

When “Prepare Mailing Labels” and "Print Questionnaire" are finished, “Mail Questionnaire & Get Responses” can start.
The later of the two EF times for “Prepare Mailing Labels” and "Print Questionnaire" is 48, therefore this is the ES.
“Mail Questionnaire & Get Responses” has an estimated duration of 65 days, so its ES is day 48 and its EF is day 113.

“Test Software”

When "Develop Data Analysis Software" and "Develop Software Test Data" are finished, “Test Software” can start.
The later of the two EF times for “Develop Data Analysis Software" and "Develop Software Test Data" is 50.
"Test Software" has an estimated duration of 5 days, so its ES is day 50 and its EF is day 55.

“Input Response Data”

When “Mail Questionnaire & Get Responses” and "Test Software" are finished, “Input Response Data” can start.
The later of the two EF times for “Mail Questionnaire & Get Responses” and "Test Software" is 113.
"Input Response Data" has an estimated duration of 7 days, so its ES is day 113 and its EF is day 120.

“Analyze Results”

When “Input Response Data” is finished on day 120, “Analyze Results” can start.
It has an estimated duration of 8 days, so its ES is day 120 and its EF is day 128.

“Prepare Report”

When “Analyze Results” is finished on day 128, “Prepare Report” can start.
It has an estimated duration of 10 days, so its ES is day 128 and its EF is day 138.

The required completion time for this entire project is 130 days. 138 days is 8 days beyond the required completion time, therefore the project was not completed in the required time.

Schedule Table ES and EF

This figure depicts the ES and EF times for the consumer market study project we just analyzed, in a schedule table format.

Latest Start and Finish Times

Latest start time (LS) is the latest time by which a specific activity must be started in order for the entire project to be finished by its required completion time.

It is calculated by subtracting the activity’s estimated duration from the activity’s latest finish time.

Latest finish time (LF) is the latest time by which a specific activity must be completed in order for the entire project to be finished by its required completion time.

It is calculated on the basis of the project required completion time and the estimated durations of succeeding activities.

LS = LF– Estimated Duration

Calculate backward through the network diagram from the end of the project to the beginning of the project.

Rule 2:

The latest finish time for a specific activity must be the same as or earlier than the earliest of all the latest start times of all the activities emerging directly from that specific activity.

Latest Start and Finish Times Calculation

These figures show two activities that emerge directly from an activity labeled, “Print Posters & Brochures.”

This project is required to be completed by day 30. Therefore, “Distribute Posters” must be started by day 20 because it has an estimated duration of 10 days, and “Mail Brochures” must be started by day 25 because it has an estimated duration of 5 days.
The earlier of these two LSs is day 20. Therefore, the latest that “Print Posters & Brochures” can finish is day 20, so that “Distribute Posters” can start by day 20.

Even though “Mail Brochures” does not have to start until day 25, “Print Posters & Brochures” must finish by day 20, or else the entire project will be delayed.
If “Print Posters & Brochures” does not finish until day 25, then “Distribute Brochures” will not be able to start until day 25.
Because “Distribute Brochures” has an estimated duration of 10 days, it will not finish until day 35, which is 5 days beyond the project required completion time.

“Prepare Report”

Now let us look at how to set up the backward calculations for the consumer market study project we just analyzed.

The required completion time for the project is 130 working days.
Therefore, the latest that “Prepare Report,” the last activity, can finish is day 130, and the latest that it can start is day 120 because its estimated duration is 10 days.
In order for “Prepare Report” to start on day 120, the latest that “Analyze Results” can finish is day 120. If the LF for “Analyze Results” is day 120, then its LS is day 112 because its estimated duration is 8 days.

“Analyze Results”

In order for “Prepare Report” to start on day 120, the latest that “Analyze Results” can finish is day 120.
If the LF for “Analyze Results” is day 120, then its LS is day 112 because its estimated duration is 8 days.
In order for “Analyze Results” to start on day 112, the latest that “Input Response Data” can finish is day 112.

“Input Response Data”

If the LF for “Input Response Data” is day 112, then its LS is day 105 because its estimated duration is 7 days.
In order for “Analyze Results” to start on day 112, the latest that “Input Response Data” can finish is day 112.
If the LF for “Input Response Data” is day 112, then its LS is day 105 because its estimated duration is 7 days.

“Test Software” and “Mail Questionnaire & Get Responses”

In order for “Input Response Data” to start on day 105, the latest that “Mail Questionnaire & Get Responses” and "Test Software" can finish is day 105.
If the LF for “Mail Questionnaire & Get Responses” is day 105, then its LS is day 40 because its estimated duration is 65 days. If the LF for "Test Software"” is day 105, then its LS is day 100 because its estimated duration is 5 days.

"Develop Data Analysis Software" and "Develop Software Test Data"

In order for “Test Software” to start on day 100, the latest that "Develop Data Analysis Software" and "Develop Software Test Data" can finish is day 100.
If the LF for “Develop Data Analysis Software” is day 100, then its LS is day 88 because its estimated duration is 12 days.
If the LF for “Develop Software Test Data” is day 100, then its LS is day 98 because its estimated duration is 2 days.

“Prepare Mailing Labels” and "Print Questionnaire”

In order for “Mail Questionnaire & Get Responses” to start on day 40, the latest that “Prepare Mailing Labels” and "Print Questionnaire" can finish is day 40.
If the LF for “Prepare Mailing Labels” is day 40, then its LS is day 38 because its estimated duration is 2 days.
If the LF for “Print Questionnaire” is day 40, then its LS is day 30 because its estimated duration is 10 days.

“Review Comments & Finalize Questionnaire”

Look at “Review Comments & Finalize Questionnaire.”
In order for the four activities emerging from this activity to start by their LS times (so that the project can finish by its required completion time of 130 days), “Review Comments & Finalize Questionnaire” must be finished by the earliest LS of all four activities, according to Rule 2.
The earliest of the four LSs is day 30, the latest time by which “Print Questionnaire” must start.
Therefore, the latest that “Review Comments & Finalize Questionnaire” can finish is day 30.
If the LF for “Review Comments & Finalize Questionnaire” is day 30, then its LS is day 25 because its estimated duration is 5 days.

“Pilot-Test Questionnaire”

In order for “Review Comments & Finalize Questionnaire” to start on day 25, the latest that “Pilot-Test Questionnaire” can finish is day 25.
If the LF for “Pilot-Test Questionnaire” is day 25, then its LS is day 5 because its estimated duration is 20 days.

“Develop Draft Questionnaire”

In order for “Pilot-Test Questionnaire” to start on day 5, the latest that “Develop Draft Questionnaire” can finish is day 5.
If the LF for “Develop Draft Questionnaire” is day 5, then its LS is day -5 because its estimated duration is10 days.

“Identify Target Consumers”

In order for “Develop Draft Questionnaire” to start on day -5, the latest that “Identify Target Consumers” can finish is day -5.
If the LF for “Input Response Data” is day -5, then its LS is day -8 because its estimated duration is 3 days.

Therefore, the consumer market study project must start 8 days earlier than the planned start date in order to finish in the required 130 days.

Schedule Table LS and LF

Here you see a figure that depicts the schedule table with the LS and LF values added.

Total Slack

Total slack is sometimes called float.
It is the difference between EF time of last activity and the project required completion time.
Total slack is calculated for each of the activities by finding the difference between the EF time of the activity and the LF of the activity.
You also look at the difference between the ES and LS of the activity.
Negative slack indicates:
A lack of slack over the entire project
The amount of time an activity must be accelerated to complete the project by the required completion time
Positive slack indicates the maximum amount of time that the activities on a particular path can be delayed without jeopardizing completion of the project by the required completion time.
If the total slack is zero, the activities on the path do not need to be accelerated, but cannot be delayed.

How much slack is in this project to put up new wallpaper?

This figure depicts a project to remove old wallpaper and put up new wallpaper.

The total completion time is 20 days. The tasks take 15 days (7+5+3).

Therefore, the project has 5 days of slack.

Critical Path

The critical path is this longest path in the overall network diagram.
One way to determine which activities make up the critical path is to find which ones have the least amount of slack.

Critical Path Through a Project

This table shows slack values for each activity in the consumer market study project we just analyzed.
Those with -8 as the total slack are the activities on the critical path.

The figure on the bottom of the slide depicts the critical path through the network diagram for the consumer market study project.

Change in Slack for Critical Path

This figure depicts the change in the critical path if the estimated duration of the Mail Questionnaire & Get Responses task is reduced from 65 days to 55 days.

Note that the tasks on the critical path now have a total slack of 2, the least amount slack in the project.

Free Slack

Free slack is the amount of time a specific activity can be postponed without delaying the earliest start time of its immediately succeeding activities.

Free slack is calculated by:

Finding the lowest of the values of total slack for all the activities entering into a specific activity
Then subtracting that value from the values of total slack for the other activities also entering into that same activity

Total Slack compared to Free Slack

Let’s look at an example of free slack.

Activities 7 and 8 are predecessors for Activity 10 in the figure above.
The values of total slack for activities 7 and 8 are 50 and 60 days, respectively.
The lesser of these two values is 50 days.
Therefore, activity 8, “Develop Software Test Data,” has a free slack of 10 days (60 – 50 = 10) and can slip by up to that amount without delaying the earliest start time of activity 10, “Test Software.”

Bar Chart Format

A Gantt chart is the name commonly used for the type of bar chart tool employed in planning and scheduling.
As you can see in the Gantt chart on this slide, the activities are listed on the left-hand side and there is a time scale along the bottom or the top.
The estimated duration for each activity is indicated by a bar spanning the period during which the activity is expected to be accomplished.
Gantt charts often also have a column that indicates who is responsible for each task.
This Gantt chart depicts the consumer market study project that we have been analyzing.
You can probably see how this is an easy way to visually represent when activities are scheduled to occur during a project.
A Gantt chart is a traditional bar chart in that it does not graphically display the dependent relationships of activities.
Be sure to create the network diagram and connect the bars in the Gantt chart with arrows to show relationships.
Project management software can automatically generate a time-scaled bar chart from the schedule table that is based on the network diagram.

Project Control Process

Here you see a figure that illustrates the steps in the project control process.

The project control process starts with establishing a baseline plan that shows how the project scope will be accomplished on schedule and within budget.
Once this baseline plan is agreed upon by the customer and the contractor or project team, the project work can be performed.
It is necessary to monitor the progress to ensure that everything is going according to the plan.
The project control process involves regularly gathering data on project performance, comparing actual performance to planned performance, and taking corrective action immediately if actual performance lags behind planned performance.
This process must occur regularly throughout the project.
Establish regular reporting meetings to compare actual to planned progress.
Gather data on actual performance.
Record information on changes to the project scope, schedule, and budget.

The key to effective project control is measuring actual progress and comparing it to planned progress on a timely and regular basis and taking any needed corrective action immediately.
Project management is a proactive approach to controlling a project to ensure that the project objective is accomplished, even when things do not go according to plan.

Effects of Actual Schedule Performance

As you probably know from real-life experience, some activities get completed on time, some are finished ahead of schedule, and others are completed later than scheduled.

The actual finish times (AFs) of completed activities will determine the earliest start and earliest finish times for the remaining activities in the network diagram, as well as the total slack.
This figure depicts the planned and actual performance of a project to remove old wallpaper and install new wallpaper.
Part (a) of the figure is a network diagram for a simple project. It shows that the earliest the project can finish is day 15 (the sum of the estimated durations of the three activities, 7 + 5 + 3).
Since the required completion time is day 20, the project has a total slack of +5 days.
Suppose that activity 1, “Remove Old Wallpaper,” is actually finished on day 10, rather than on day 7 as planned, because it turns out to be more difficult than anticipated.
Part (b) of the figure depicts this deviation from the original plan.
The earliest start and finish times for activities 2 and 3 will be 3 days later than on the original schedule.
Because “Remove Old Wallpaper” is actually finished on day 10, the ES for “Patch Walls” will be day 10 and its EF will be day 15.
Following through with the forward calculations, we find that “Put Up New Wallpaper” will have an ES of day 15 and an EF of day 18.
Comparing this new EF of the last activity to the required completion time of day 20, we find a difference of 2 days. The total slack got worse—it changed in a negative direction, from +5 days to +2 days.
This example illustrates how the actual finish times of activities have a ripple effect, altering the remaining activities’ earliest start and finish times and the total slack.

Incorporate Changes into Schedule

Throughout a project, changes may occur that impact the schedule.

Changes might be initiated by the customer or the project team, or they might be the result of an unanticipated occurrence.
Changes requested early in the project may have less of an impact on schedule and budget than those requested later in the project.
When the customer requests a change, the contractor or project team should estimate the impact on the project schedule and budget and then obtain customer approval before proceeding.
If the customer approves the proposed revisions to the project schedule and budget, then any additional activities, revised estimated durations, and revised estimated resources and associated costs should be incorporated into the project schedule and budget.
With respect to the project schedule, changes can result in the addition or deletion of activities, re-sequencing of activities, changes to estimated durations for specific activities, or a new required completion time for the project.

Update Project Schedule

An updated project schedule should be generated regularly that forecasts whether the project will finish ahead of or behind its required completion time, or on time.

Once data have been collected on the actual finish times of completed activities and the effects of any project changes, an updated project schedule can be calculated.
Earliest start and finish times for the remaining, uncompleted, activities are calculated by working forward through the network.
They are based on the actual finish times of completed activities and the estimated durations of the uncompleted activities.
The latest start and finish times for the uncompleted activities are calculated by working backward through the network.
An important part of updating project schedules is determining if any changes have occurred on the critical path.

How does the schedule change for the updated project?

Take a look at the updated project depicted in this figure.

1. Completed activities:

Activity 1, “Identify Target Consumers,” actually finished on day 2.
Activity 2, “Develop Draft Questionnaire,” actually finished on day 11.
Activity 3, “Pilot-Test Questionnaire,” actually finished on day 30.

2. Project changes:

It was discovered that the database to be used to prepare the mailing labels was not updated. A new database needs to be purchased before the mailing labels can be prepared. This new database was ordered on day 23. It will take 21 days to get it from the supplier.
A preliminary review of comments from the pilot test of the questionnaire indicates that substantial revisions to the questionnaire are required. Therefore, the duration estimate for activity 4 needs to be increased from 5 days to 15 days.

Here you see the updated schedule.

Note that the total slack for the critical path is now –5 days, instead of the +2 days in that was depicted in the baseline schedule.

The anticipated project completion time is now day 135, which is beyond the required completion time of 130 days.

Control Schedule

Schedule control involves four steps:

Analyzing the schedule to determine which areas may need corrective action
Deciding what specific corrective actions should be taken
Revising the plan to incorporate the chosen corrective actions
Recalculating the schedule to evaluate the effects of the planned corrective actions

If the planned corrective actions do not result in an acceptable schedule, these steps need to be repeated.
A concentrated effort to accelerate project progress must be applied to the paths with negative slack.
Activities that are near term (that is, that are in progress or to be started in the immediate future)
Activities that have long estimated durations
The amount of slack should determine the priority with which these concentrated efforts are applied.
A change in the estimated duration of any activity on that path will cause a corresponding change in the slack for that path and may shift the critical path.
Eliminating negative slack by reducing durations of activities will involve a trade-off in the form of an increase in costs or a reduction in the scope of the project.

Now that you have analyzed the changes to this project, now think about how this project must be changed in order to finish in the required 130 days.

Again, you see the network diagram that incorporates changes to the activities in the project.

1. Completed activities:

Activity 1, “Identify Target Consumers,” actually finished on day 2.
Activity 2, “Develop Draft Questionnaire,” actually finished on day 11.
Activity 3, “Pilot-Test Questionnaire,” actually finished on day 30.

2. Project changes:

It was discovered that the database to be used to prepare the mailing labels was not updated. A new database needs to be purchased before the mailing labels can be prepared. This new database was ordered on day 23. It will take 21 days to get it from the supplier.
A preliminary review of comments from the pilot test of the questionnaire indicates that substantial revisions to the questionnaire are required. Therefore, the duration estimate for activity 4 needs to be increased from 5 days to 15 days.

Here you see the updated schedule.
Note that the total slack for the critical path is now –5 days, instead of the +2 days in that was depicted in the baseline schedule.
The anticipated project completion time is now day 135, which is beyond the required completion time of 130 days.

How would you make changes to this project so that it is completed on time?

Possible responses:

Reduce time for activity 4.
Reduce time for activity 6.
Reduce time for activity 9.

Ask: If we reduce the time to complete activity 9 by 5 days, what is the impact on the number of responses? This task has already been reduced once by 10 days.

Scheduling for Information Systems Development

Scheduling the development of an information system is a challenging process.

Scheduling is often done in a haphazard manner, and, as a result, a large number of IS projects are finished much later than originally promised– or never finished at all.

Among the common problems that often push IS development projects beyond their required completion time are:

Failure to identify all user requirements
Failure to identify user requirements properly
Continuing growth of project scope
Underestimating learning curves for new software packages
Incompatible hardware
Logical design flaws
Poor selection of software
Failure to select the best design strategy
Data incompatibility issues
Failure to perform all phases of the SDLC

IS Example: Activities, Predecessors, Durations

This figure depicts a list of activities, immediate predecessors, and estimated durations for the web-based reporting system project.

The project is required to be completed in 50 days, and it needs to be started as soon as possible.

Ask: Do you think the project can be completed in 50 days?

IS Example: ES and EF Times

Here you see the ES and EF times for each activity in the web-based reporting system project.

Ask: Can you explain the different ES and EF values for the activities?

IS Example: LS and LF Times

This figure depicts the LS and LF times for each activity.

Ask: Can you explain the LS and LF values for the activities?

IS Example: Schedule Table

This table depicts the project schedule table with the calculated total slack values for each activity.

Ask: Take a minute to analyze this. What is the critical path? How can the project be finished in 50 days?

IS Example: Critical Path

This figure provides you with a visual representation of the critical path for the development project.

The team must determine a way to reduce the development time by 9 days, request that the project completion date be extended from 50 to 59 days, or find some compromise.

IS Example: Updated Network Diagram

Beth and her team proceeded with the project and completed activities 1 through 6:

Activity 1, “Gather Data,” actually finished on day 4
Activity 2, “Study Feasibility,” actually finished on day 4
Activity 3, “Prepare Problem Definition Report,” actually finished on day 5
Activity 4, “Interview Users,” actually finished on day 10
Activity 5, “Study Existing System,” actually finished on day 15
Activity 6, “Define User Requirements,” actually finished on day 18

IS Example: Updated Schedule Table

Here you see the updated project schedule.

Note that the critical path has now been reduced to zero with the updates and changes.

Project Management Information Systems

Almost all project management information systems allow you to perform the scheduling functions identified in this chapter.
Software will also calculate ES, EF, LS, and LF times, total and free slack, and the critical path
It is important, however, for the project manager to understand what these terms are and what the calculations mean
Do not rely on computers too much!
Virtually all project management information systems also allow you to perform the control functions identified in this chapter.
While an activity is in progress or once an activity has been completed, current information can be entered into the system and the software will automatically revise the project schedule.

13. Agile Project Management

The roles of the participants involved in the scrum approach include

The agile project management process includes

1. Establishing the rationale, description, funding amount, and target completion date for the final end product (deliverable) and authorizing the project.

2. Defining the product requirements and creating an ordered product backlog of prioritized specific requirements and product features.

5. At the end of the sprint, there is a sprint review meeting at which the development team reviews the work that has been accomplished as well as which items were not completed.

The person who will be responsible for performing the activity should estimate the duration for that activity. This generates commitment from the person.
The estimated duration for an activity must be based on the types and quantities of resources required to perform the activity.
Activity estimated durations should be aggressive yet realistic.
Activities should not be longer in estimated duration than the time intervals at which the actual progress will be reviewed and compared to planned progress.
Project management involves a proactive approach to controlling a project to ensure that the project objective is accomplished even when things do not go according to plan.
Once the project starts, it is important to monitor progress to ensure that everything is going according to plan.
The key to effective project control is measuring actual progress and comparing it to planned progress on a timely and regular basis and taking any needed corrective action immediately.
The key to effective schedule control is to address any paths with negative or deteriorating slack values aggressively as soon as they are identified. A concentrated effort to accelerate project progress must be applied to these paths.

The amount of negative slack should determine the priority for applying these concentrated efforts.
When attempting to reduce the duration of a path of activities that has negative slack, focus on activities that are near term and on activities that have long estimated durations.
Addressing schedule problems early will minimize the negative impact on scope and budget.
If a project falls too far behind, getting it back on schedule becomes more difficult, and usually requires spending more money or reducing the scope or quality.
If corrective actions are necessary, decisions must be made regarding a trade-off of scope, time, and cost.
A regular reporting period should be established for comparing actual progress to planned progress.
The shorter the reporting period, the better the chances of identifying problems early and taking corrective actions.
During each reporting period, data on actual performance and information on changes to the project scope, schedule, and budget need to be collected in a timely manner and used to calculate an updated schedule and budget.

The scheduling function depends on the planning function.
The estimated types and quantities of resources required for an activity, together with the availability of those resources, will influence the estimated duration for how long it will take to perform the activity.
The estimated duration for each activity must be the total elapsed time—the time for the work to be done plus any associated waiting time.
The estimate should be aggressive yet realistic.
It may be easier to estimate the durations for near-term activities, but as the project progresses, the project team can progressively elaborate the estimated the durations as more information becomes known to allow for more accurate estimated durations.
A project schedule provides a timetable for each activity and shows the earliest start (ES) and earliest finish (EF) times and the latest start (LS) and latest finish (LF) times for each activity.
The total slack for a particular path of activities through the network is common to and shared among all activities on that path.

The critical path is the longest (most time-consuming) path of activities in the network diagram.
The key to effective project control is measuring actual progress and comparing it to planned progress on a timely and regular basis and taking any needed corrective action immediately.
Actual progress—whether faster or slower than planned—will have an effect on the schedule of the remaining, incomplete activities of the project.
Any type of change—whether initiated by the customer, the contractor, the project manager, a team member, or an unanticipated event—will require a modification to the plan in terms of scope, schedule, and/or budget.
Schedule control involves four steps: analyzing the schedule to determine which areas may need corrective action, deciding what specific corrective actions should be taken, revising the plan to incorporate the chosen corrective actions, and recalculating the schedule to evaluate the effects of the planned corrective actions.
One of the most important factors in effective scheduling is estimating activity durations that are as realistic as possible.

1. Why does the scheduling function depend on the planning function? Which one must be done first? Why?

A schedule is a timetable for a plan.
It cannot be established until the plan has been developed.

2. Describe what an activity estimated duration is. How is it determined?

The duration estimate for each activity is the total elapsed time for the work to be done, plus any associated waiting time.
An activity’s duration estimate must be based on the quantity of resources expected to be used on the activity. The estimate should be aggressive, yet realistic.
A Beta distribution using most likely, pessimistic, and optimistic times can be helpful when envisioning the big picture of how long activities are going to take.

It can be helpful to think about a project in terms of number of days from the start in case the project start is delayed for some reason, such as an unexpected snowstorm delaying the start of a construction project.
Example: A project that requires 100 days to complete with a finish date that is dependent upon the work being completed, rather than on a specific date

4. Refer to the figure below, Figure 5.4 from the text. Why is the earliest start time for “Review Comments & Finalize Questionnaire” day 33? Why is the earliest finish time day 38?

The task cannot start until its predecessor is finished, which is day 33.
The task has a duration of 5, so it will finish on day 38.

5. Refer to the figure below, Figure 5.7. Why is the latest start time for “Mail Questionnaires & Get Responses” day 40? Why is the latest finish time day 105?

Because its predecessor’s latest start time is day 105, the task must finish by day 105.
It has a duration of 65, so it must start by day 40.

6. Describe the different types of project slack. How is each calculated?

Total Slack is the amount of time an activity’s earliest finish time can be delayed without delaying succeeding tasks beyond their latest finish times.

If it is positive, you have extra time that can be used if needed.
If it is negative, the activity needs to be completed by its latest finish time or the project completion will be delayed.
Slack = LF – EF or Slack = LS – ES
Free Slack is calculated by finding the lowest of the values of total slack for all the activities entering into a specific activity, and then subtracting it from the values of total slack for the other activities also entering into that same activity.

Note: A numbering change happened in the printing of the first run of the seventh edition. Question 7 was moved to be part of Question 6 and Question 9 was split to be questions 8 & 9.

7. Why is it important to determine the critical path of a project? What happens if activities on this path are delayed? What happens if activities on this path are accelerated?

If any activity on the critical path is delayed, the whole project will be delayed, so it is important to know what the critical path is.
If any of these activities are accelerated, the project completion date will also be accelerated.

Note: A numbering change happened in the printing of the first run of the seventh edition. Question 7 was moved to be part of Question 6 and Question 9 was split to be questions 8 & 9.

8. From your experience, describe how you have used a project control process. If you did not use continual monitoring of the progress, how would this have helped improve the project’s success?

Specific answers will vary. Students’ answers should include setting a baseline for the project plan and monitoring and controlling the actual project progress.

Note: A numbering change happened in the printing of the first run of the seventh edition. Question 7 was moved to be part of Question 6 and Question 9 was split to be questions 8 & 9.

9. Why should a project have a regular reporting period? Should all projects have the same reporting period? Why or why not? What types of data should be collected during each reporting period?

A regular reporting period should be established so that actual progress can be compared to planned progress and any discrepancies can be dealt with as early as possible. The period depends on the complexity or duration of the project. It may be daily, weekly, bi-weekly, or monthly.
Two kinds of data need to be collected:
Data on actual performance
This includes the actual time that activities were started and/or finished and the actual costs expended and committed
Information on any changes to the project scope, schedule, and budget

Note: A numbering change happened in the printing of the first run of the seventh edition. Question 7 was moved to be part of Question 6 and Question 9 was split to be questions 8 & 9.

10. Who can initiate changes to a project schedule? Describe why and when changes would occur in a project. How are the network diagram and schedule updated to reflect the changes?

Changes might be initiated by the customer or the project team, or they might be the result of an unanticipated occurrence.
A change might be initiated in order to add an activity, eliminate an activity or modify some aspect of an activity.
Changes can occur at any time throughout the project.
If they are requested early in the project, they may have less impact on cost and schedule.
Specific examples will vary for describing why and when changes would occur in a project.
Answers for how the network diagram and schedule are updated should include a recalculation of ES, EF, LS, and LF for the project.

11. Describe how you would apply the four steps of schedule control to a project. If the project needs to be accelerated, what kinds of activities would be the primary focus? Why?

Schedule control involves four steps:
Analyzing the schedule to determine which areas may need corrective action
Deciding what specific corrective actions should be taken
Revising the plan to incorporate the chosen corrective actions
Recalculating the schedule to evaluate the effects of the planned corrective actions
Specific examples will vary. Answers will depend upon the project example. Accelerate near-term and longer-duration activities that are on the critical path.

12. Why is the scheduling of IS projects so challenging? What are some of the common problems that push IS projects beyond their due dates?

Scheduling for IS is often done in a haphazard manner, and thus a large percentage of IS projects are finished much later than originally promised— or never finished at all. One of the most important factors in effective scheduling is arriving at activity duration estimates that are as realistic as possible.
Among the common problems that often push IS development projects beyond their required completion time are the following:
Failure to identify all user requirements
Failure to properly identify user requirements
Continuing growth of project scope
Underestimating learning curves for new software packages
Incompatible hardware
Logical design flaws
Poor selection of software
Failure to select the best design strategy
Data incompatibility issues
Failure to perform all phases of the SDLC

(See the figure on the slide above)

The longest path in the network is: A-B-E-G-H.
Yes, the project can be completed within 40 weeks. With the current estimates, it will take 36 weeks.
With the changes, the project can still be completed within 40 weeks.
However, the expected completion has slipped from 36 to 38 weeks. If there is a need to speed it back up, attention should be given to Activity F.

13. Calculate the ES, EF, LS, and LF times and the slack for each activity in the figure below and identify the critical path for the project. Can the project be completed in 40 weeks? Assume that activity A actually finished at 3 weeks, activity B actually finished at 12 weeks, and activity C actually finished at 13 weeks. Recalculate the expected project completion time. Which activities would you focus on in order to get the project back on schedule?

Here is the schedule table for Question 13 from the previous slide.

13. Calculate the ES, EF, LS, and LF times and the slack for each activity in the figure below and identify the critical path for the project. Can the project be completed in 40 weeks? Assume that activity A actually finished at 3 weeks, activity B actually finished at 12 weeks, and activity C actually finished at 13 weeks. Recalculate the expected project completion time. Which activities would you focus on in order to get the project back on schedule?

Here is the schedule table for Question 13, after the proposed changes in activity finish times are make.

The critical path is: 1-2-4-7-8-9.
No, this project cannot be completed within 30 weeks. With the current estimates, it will take 35 weeks.
The project has slipped even further. With the current estimates, it will take 36 weeks. Attention should be given to all activities since they all have negative slack. However, the path 6-8-9 is the most critical.

(Here is the schedule table for Question 14 from the previous slide)

(Here is the schedule table, reflecting the changes from part 3 of Question 14)

The most critical path in the network is: B – D – F – G – H – J.
No, this project cannot be completed within 30 weeks. With the current estimates, it will take 32 weeks.
Even with the changes in finish time, the project is still 2 weeks behind the scheduled completion date. Attention should be given to activities D – F – G – H – J.

(Here is the schedule table for Question 15 from the previous slide)

(Here is the schedule table from part 3 of Question 15)

Internet Exercises

Assign the Internet Exercises to your students as homework or complete them together in a computer lab.

Internet Exercises

Assign the Internet Exercises to your students as homework or complete them together in a computer lab.

2. For exercises 2 through 5, visit the website for Mind Tools ™ . Explore the site. What information does it provide?

3. Click on the link for "What’s New" and describe what you find.

What’s New are categorized by topics such as project planning, scheduling, and Microsoft Project.

4. Click on the "Toolkit" link. Read through a topic that interests you. Provide a one-page summary..

Case Study #1: A Not-For-Profit Medical Research Center

This case continues through to chapter 8. Each chapter has questions to reinforce the concepts presented. Have students save their work for this case study for the work they will do in chapters 6 to 8.
This is an open-ended case study, so encourage students to use their creativity.
As the director of external affairs for a national not-for-profit medical research center you are tasked with producing a shorter, simpler, easy-to-read annual report to show the benefits of the center's research and the impact on people's lives in an effort to help raise funds for the center.

Group Activity

Form groups of three to five members. Have each group perform the assigned tasks. Allow each group to present their answers.

1. Develop an estimated duration for each activity.

Responses should use the list of tasks developed in chapter 4 and include the estimated duration for each task.

Responses could be presented in a network diagram or in the schedule table format– either would be correct.
The project should finish in 180 days.
If the original plan is not completed by 180 days, the responses should describe what tasks were revised to meet the required completion date.

3. Determine the critical path and identify the activities that make up the critical path.

Responses can be presented in a list of activity names, highlighted in the network diagram, or highlighted in the schedule table.

4. Produce a bar chart (Gantt Chart) based on the ES and EF times from the schedule in item 2.

The bar chart can be drawn or produced using a project management information system like Microsoft Project.
Suggest that students might want to include arrows to show the dependencies of the bars.

Case Study #2: The Wedding

This case continues through to chapter 8. Each chapter has questions to reinforce the concepts presented. Have students save their work for this case study for the work they will do in chapters 6 to 8.
This is an open-ended case study. The students have the opportunity to be very creative on this one. Encourage that creativity.
Tony and Peggy Sue want to get married and have family that want to plan the wedding for them without considering what Tony or Peggy Sue would want.

Group Activity

Form groups of three to five members. Have each group perform their assigned tasks. Allow each group to present their answers.

1. Develop an estimated duration for each activity.

Responses should use the list of tasks developed in chapter 4 and include the estimated duration for each task.

Responses could be presented in a network diagram or in the schedule table format.
The project should finish in 180 days.
If the original plan is not completed by 180 days, the responses should describe what tasks were revised to meet the required completion date.

3. Determine the critical path and identify the activities that make up the critical path.

Responses can be presented in a list of activity names, highlighted in the network diagram, or highlighted in the schedule table.

4. Produce a bar chart (Gantt Chart) based on the ES and EF times from the schedule in item 2.

The bar chart can be drawn or produced using a project management information system like Microsoft Project.
Suggest that students include arrows to show the dependencies of the bars.

Activity Duration Estimates

With projects for which there is a high degree of uncertainty about the activity duration estimates, it is possible to use three estimates for each activity:

Optimistic time (to) is the time in which a particular activity can be completed if everything goes perfectly well.
Most likely time (tm) is the time in which a particular activity is completed under normal conditions.
Pessimistic time (tp) is the time in which a particular activity can be completed under adverse circumstances.

Establishing these three time estimates makes it possible to take uncertainty into account when estimating how long an activity will take.

The Beta Probability Distribution

In network planning, when three time estimates are used for each activity, it is assumed that the three estimates follow a beta probability distribution.

The expected duration is calculated using the following formula: te = (to + 4(tm) + tp)/6

The figure above depicts the beta probability distribution.

Probability Fundamentals

Network planning in which three time estimates are used for each activity can be considered a stochastic, or probabilistic, technique, since these calculations allow for uncertainty.
Any technique that uses only one time estimate is considered to be a deterministic technique. If only one time estimate is used for each activity, probability calculations cannot be made.
The central limit theorem of probability theory states that the total probability distribution is not a beta probability distribution, but a normal probability distribution.
The variance for the beta probability distribution of an activity is found with the following formula: Variance = s2 = ((tp – to)/6)2
Note that the variance of the normal distribution is the sum of the variances of the beta distribution.
The standard deviation, s, is another measure of the dispersion of a distribution and is equal to the square root of the variance.
The total probability distribution of all the activities on the critical path of a network diagram is a normal distribution, with a mean equal to the sum of the individual activity expected durations and a variance equal to the sum of the individual activity variances.
Review the example presented in the book. Especially refer to figures 5.28 and 5.29.

Normal Probability Distribution

Here one sees an illustration of the normal probably distribution.

Example Project

Here is an example of how you can calculate the variance for three different activities, using the formula for finding variance te = (to + 4(tm) + tp)/6.

The rectangle below each activity shows the optimistic, most likely and pessimistic completion times.