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Chapter 8 Project Time Management

The project scope identifies the objectives of the project, what activities will be performed,

and some of the activities that are not included in the project. The scope document is used

to create a master schedule that identifies important dates and activities. In this chapter,

the student learns how the scope and schedule are developed.

Project planning and scheduling is both an art and a science. No two project managers or

planning professionals develop identical plans or project schedules. The planning process

is creative and reflects the planner’s approach and style. Even though the project plan is

unique to the approach and style of the planner, methods for developing the schedule and

documenting the resulting plan follow certain rules.

On larger and more complex projects, a planning function composed of a small team of

planning and scheduling experts may be needed to develop and track the project schedule.

This text was adapted by The Saylor Foundation under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License without attribution as

requested by the work’s original creator or licensee.

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Project planners facilitate the development of the information required to develop the

project plan using templates, past or similar projects, and most importantly, the thoughts

and plans of the project team leaders and members. On a smaller project, the project

manager may be responsible for accomplishing this planning function.

After gathering this information, the planner begins developing the

project’s master schedule—a summary level schedule that encompasses the entire project

scope—that includes major events and provides a view of the entire project. Working with

the project team, the planning continues to include more details as additional information

becomes available. The schedule continues to evolve during the life of the project, and

major revisions may be necessary in response to events both inside and outside the project

that change critical dates on the schedule.

Determining the schedule of activities that comprise the project is a key element of project

management.

8.1 Types of Schedules L E A R N I N G O B J E C T I V E

1. Define the types of project schedules.

The schedule develops as the project moves from its early conceptual phase into the

execution phase.

Conceptual

When the scope of the project is being determined, a simple schedule that shows the major

tasks and approximate start and end dates is developed to allow senior management to

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make decisions about the scope of the project. Detail is not required at this stage because

entire tasks might be dropped from the scope, or the whole project might not be approved.

Master

If the project is chosen, a master schedule is created. It has major events and dates such as

the starting date and the completion date. The master schedule is often part of a contract.

Changes to the master schedule must be approved using a documented change process

with approval by the project sponsor and client.

Detail

To execute the master schedule, the major activities are broken down into smaller

activities and resources are assigned to those activities. The most detailed versions or

portions of the schedule may be developed a few weeks prior to the execution of those

activities and are called two-week plans. Portions of the master schedule that affect

particular vendors might be sent to them so they can provide detailed activities that they

would perform.

K E Y T A K E A W A Y Types of schedules vary in detail. A broad, general conceptual schedule is used in the

earliest phases of the project design. A master schedule with start date, milestones,

and completion date becomes part of the contract and is changed by mutual

agreement using a formal change process. Details are added to the master schedule as

needed to perform the work of the project activities.

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8.2 Elements of Time Management L E A R N I N G O B J E C T I V E S

1. Describe a work breakdown structure and how it relates to activities.

2. Describe the use of graphic representations for time management.

According to the Project Management Institute (PMI), project time management includes

the following elements: [1]

Define activities

Sequence activities

Estimate activity resources

Estimate activity durations

Develop schedule

Control schedule

The list of activities, their relationship to each other, and estimates of durations and

required resources comprise the work breakdown structure (WBS). The project WBS is

a hierarchical—classified according to criteria into successive levels—listing and grouping

of the project activities required to produce the deliverables of the project. The WBS

represents a breakdown of the project into components that encompass the entire scope of

the project. Each level of the WBS hierarchy represents a more detailed description of the

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project work so that the highest level represents broad categories, and the lower levels

represent increasing amounts of detail.

Larger and more complex projects often require a larger WBS. The size of the WBS is

directly related to the amount of work on the project and how that work is divided into

work packages. The WBS can be developed around the project phases or the project units

or functions that will be performing the work. A WBS organized around the project phases

facilitates the understanding of the amount of work required for each phase of the project.

A WBS developed around the project units or functions of the project facilitates the

understanding of the amount of work required for each function.

The following example, named John’s move, has a low level of complexity compared to a

larger project. Normally, this project would not receive the amount of detailed planning

described in the following examples, but the authors chose to use a basic project that is

familiar to most students to help them focus on learning the new concepts.

Changing Jobs John has a small but important project. He has accepted a job in Atlanta and now has to

move from Chicago to Atlanta and be there, ready to work, right after the Christmas

holidays. If the furniture arrives in good condition at least two days before John starts

work, and for less than Five thousand dollars, the project will be a success. The move to

Chicago five years ago cost five thousand dollars, but John is smarter now and will use his

friends to help, so he is confident he can stay within budget.

Developing a WBS begins by defining and developing lists of all activities—work performed

on the project that consumes project resources, including cost and time—needed to

accomplish the work of the project. The first draft of the WBS includes activities at the

highest level of the hierarchy or the management level and typically includes the major

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activities or summary activities required to accomplish the deliverables identified in the

project scope of work.

Top-Level Activities in Move Planning On John’s move project, these top-level activities are numbered 1.0, 2.0, 3.0, and so on. For

example, a plan for the move is the major deliverable from 1.0 Plan Move, as shown below.

Figure 8.3Top Level of WBS

The work breakdown structure is then decomposed—broken down into smaller units. The

1.1, 1.2, and 1.3 numbers are the first subdivision of the work. For example, one of John’s

Summary Level Activities is Packing (3.0). Although some minor packing (delicate items:

2.4) are packed under another summary activity, 3.3 is the major packing and includes the

coordination and support of labor (friends Dion and Carlita). The activity is then

decomposed—separated into basic elements—to the next level by listing the individual

rooms that need packed, as shown below.

Figure 8.4Major Activity Decomposed into Smaller Activities

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The WBS could be decomposed further to a greater level of detail by listing the tasks

needed for each activity. For example activity 3.3.3, Pack Bedroom, can be decomposed into

additional tasks, such as 3.3.3.1 Pack Closet, 3.3.3.2 Pack Drawers, and 3.3.3.3 Pack

Blankets. This type of numbering of the activities is called intelligent numbering. In

intelligent numbering, the numbering system has meaning so that a member of the project

team knows something about the activity by the number of the activity. For example, any

activity associated with packing begins with a 3; even picking up donuts can be an activity

that supports packing. The donuts are a form of payment for the labor of Dion and Carlita.

The WBS is developed or decomposed to the level that the manager needs to control or

manage the project. Typically, larger and more complex projects require a more detailed

WBS.

Estimation of Duration

After the project team has created the WBS, each activity is reviewed and evaluated to

determine the duration (how long it will take to accomplish from beginning to end) and

what resources(time, materials, facilities, and equipment) are needed. An estimate is an

educated guess based on knowledge, experience, and inference—the process of deriving

conclusions based on assumptions. The accuracy of the estimate is related to the quality of

the knowledge and how that knowledge is applied. The person with the most knowledge

may not be the most objective person to provide duration estimates. The person

responsible for the work may also want to build in extra time. Multiple inputs into the

duration estimate and a more detailed WBS help reduce bias—the making of decisions

based on a prejudged perspective.

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The unit of time used to develop the activity duration is a function of the level of detail

needed by the user of the schedule. The larger and more complex the project, the greater

the need for detail, which usually translates into shorter durations for activities.

Duration Estimate for Training On a new plant start-up, the plant manager may need to know when the new employees

will start training, when they will be fully trained, and when they can begin working in the

plant. The plant human resources manager may need to know what skills workers need

and how much time each training class will take. The schedule detail the HR manager needs

will include activities to locate facilities, schedule training, write contracts for trainers, and

manage the initiation of training classes. The trainer will need an even greater level of

detail, which could be measured in days or even hours.

On our John’s move example, the project schedule may have been just as effective without

detailing the packing of the individual rooms in the old apartment. If we deleted these

items, would John know when he needed to pack each one of these rooms? If the answer is

yes, then we may not need that level of detail.

The activity duration is the length of time the activity should take to complete from

beginning to end. The unit of duration is typically working days but could include other

units of time such as hours, weeks, or months. The unit chosen should be used consistently

throughout the schedule.

An important event, such as a ground-breaking ceremony or receipt of occupancy from the

building inspector, is called a milestone. A milestone has no duration or resources. It is

simply an indicator of an important point in the project.

Resource Allocation and Calendars

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A common resource constraint is availability. To consider the availability of team members,

consultants, and key pieces of equipment, you can create a resource calendar for each that

indicates which days are available and which are days off for a group, an individual, or a

project asset such as a piece of important equipment. A calendar for team members from

the same company could be the company calendar that shows working days, weekend

days, and holidays. Individual team members can have individual calendars that show their

vacation days or other days off, such as parental leave days. If major pieces of equipment

are only available for certain periods of time, they can be given a resource calendar.

Resource calendars become important tools when changes must be made to the schedule.

When a resource calendar is applied to a duration estimate, the duration in days is

distributed across the available calendar days. For example, if the duration is three days

and the start date of the activity is Thursday, the activity would begin on Thursday and end

on Monday of the following week, assuming the resource calendar shows that the person

has the weekend off. If the weekend included an extra day off for a holiday like Labor Day,

shown in the calendar in Figure 8.6, the completion day of the same three-day activity

would be pushed to Tuesday.

Figure 8.6

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Nonworking days can be designated in a calendar.

Activity Sequencing

Determining the schedule of a project begins by examining each activity in the WBS to

determine its relationship to the other activities.

Project Logic

The project logic is the development of the activity sequence or determining the order in

which the activities will be completed. The process for developing the project logic involves

identifying the predecessors—activities that come before—and successors—the activities

that come after.

Project Logic for John’s Move In our example of John’s move, contacting Dion and Carlita—activity 1.1—comes before the

lunch meeting is scheduled. You must logically contact Dion and Carlita before you

schedule your Host Planning Lunch—activity 1.2. Your conversation with Dion and Carlita

will provide you with dates they are available and establish their commitment to help you

move. Therefore, the conversation with Dion and Carlita is a predecessor to the Host

Planning Lunch Activity. This relationship is diagramed below.

Figure 8.7Relationship between Two Activities

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These terms define a relationship that is similar to a family relationship like father and son.

The father exists in time before the son. Similarly, each element of the diagram can have

predecessor-successor relationships with other elements, just like a father can be the son

of someone else. Unlike the biological father-son relationship, activities can have more than

one predecessor.

The relationship between a predecessor activity and a successor activity is called

a dependency. The successor activity starts after and is dependent on the predecessor

activity. Because the conversation with Dion and Carlita must take place before a planning

meeting can be scheduled, this is called a natural dependency because the relationship can

be inferred logically. Activities that have predecessor-successor relationships

occur sequentially—one after the other. Another term for this type of relationship is finish-

start, which means the first activity must finish before the next one can start. Refer to the

figure above.

Some activities take place concurrently—at the same time. If they must begin at the same

time, they have a start-start relationship. If the activities can start at different times but

they must finish at the same time, they have a finish-finish relationship. Refer to Figure 8.8.

Figure 8.8

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Concurrent activities can be constrained to finish at the same time or start at the same

time.

Predecessor Relationships in John’s Move The figure below shows the activities in John’s move with the predecessors identified for

thePlan Move and Prepacking groups of activities. Because the finish-start relationship is by

far the most common, the type of relationship is assumed to be finish-start unless

otherwise mentioned.

Figure 8.9Outline of Activities with Predecessors Identified

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Lag and Lead Times

Most activities in a network diagram have a finish-start relationship. If a certain amount of

time must go by before a successor activity can begin, the required delay is called lag time.

For example, concrete does not reach its full strength for several days after it is poured. Lag

time is required between the end of the pouring process and the beginning of construction

that puts stress on the concrete as diagrammed in Figure 8.10. Similarly, you must allow lag

time for payment checks to be processed by the banking system before you can spend the

money.

Figure 8.10

Required time between activities is lag time.

In some cases, the successor activity can overlap the end of its predecessor activity and

begin before the predecessor is finished. This is called lead time.

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Lead Time in John’s Move In John’s move, you might begin separating the small and delicate items that will be packed

in step 2.3 before you get the packing materials in step 2.1 so that when the materials are

available, step 2.3 is already partially completed. If the preparing the small items for

packing can overlap its predecessor and shortens the time it takes to accomplish both tasks

by a day, it has a lead time of one day.

Figure 8.11

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Overlap is called the lead time of the successor activity.

The characteristics and identifiers of an activity are its attributes.

At this point in the process of analyzing John’s move, each activity has an identifying code, a

short description, predecessors, and lead or lag times, as shown in a partial table of

activities in Figure 8.12 "Table of Attributes".

Figure 8.12 Table of Attributes

Milestones

Milestones are significant events in your project. An effective milestone schedule will

capture the major constraints to the project schedule and provide a summary level

overview of the project. Even though milestone events are significant to the project, they

consume no resources and have no duration. Milestones are usually indicated on the

project schedule with a diamond and often have a vertical line on a time-scaled graph to

show the relationship of various schedule paths to the milestone.

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In our John’s move project, we might create a milestone called “all packing complete” to

represent the date when everything is packed and ready for the moving van. Any delay in

this date will mean a delay in the arrival of the moving van in Chicago, a delay in the arrival

of the moving van in Atlanta, and a delay of all the unpacking and other downstream

activities. See Figure 8.13 "Gantt Chart".

Graphic Representations

Relationships between activities are easier to recognize if they are presented using

graphics such as bar charts or a network of connected boxes.

Bar Charts

The type of bar chart used to illustrate activity relationships in a project is the Gantt chart.

The Gantt chart was developed by Henry Gantt and used on major projects, including

building the Hoover Dam and the U.S. interstate highway system. [2] The Gantt chart, also

called a bar chart, is a time-scaled graphic that represents each activity with a bar that

reflects the duration, start, and finish time, as shown in Figure 8.13 "Gantt Chart".

Figure 8.13 Gantt Chart

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A Gantt chart is easy to read and provides sufficient information for project team members

to plan activities within a short time frame. For many larger projects, a two-week bar chart,

extracted from the larger master schedule, provides the information needed for team

members and contractors to coordinate activity details. The Gantt chart provides

information for simple planning but is limited because a Gantt chart does not illustrate

complex relationships well.

Network Diagrams

People recognize relationships and patterns more effectively when they look at diagrams

like the one in Figure 8.14 "Project Network Diagram".

The precedence diagram method (PDM) is a technique for graphically displaying the logic

of the schedule by placing the activities in boxes with arrows between them to show the

precedence-successor relationships. The boxes in this type of diagram are called nodes and

the arrows indicate finish-start relationships. Compare the diagram in Figure 8.14 "Project

Network Diagram" to the outline in Figure 8.9 "Outline of Activities with Predecessors

Identified" to see how much easier it is to trace a sequential path from one activity to the

next in the precedence diagram. This type of diagram is also called

aproject network diagram.

Figure 8.14 Project Network Diagram

K E Y T A K E A W A Y S

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The work breakdown structure is a list of activities, including estimates of their

durations, their relationships with others, and the resources assigned to them.

Bar charts are used to indicate durations and sequencing where the relationships are

simple. Network diagrams are used to show complex relationships between activities.

[1] Project Management Institute, Inc., A Guide to the Project Management Body of Knowledge

(PMBOK Guide), 4th ed. (Newtown Square, PA: Project Management Institute, Inc., 2008), 129.

[2] Reference.com, “Henry

Gantt,” http://www.reference.com/browse/wiki/Henry_Gantt (accessed July 27, 2009).

8.3 Critical Path and Float

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L E A R N I N G O B J E C T I V E 1. Calculate critical path, project float, early start dates, and late start dates.

The critical path is the path through the network that results in the latest completion date

of the project.

If any activity on the critical path is delayed, the completion of the project will be delayed

by an equal amount. It is the path with the greatest total duration. To determine the critical

path, add the amount of time estimated for the duration of each activity to the previous

activity to determine which path through the network has the longest total duration, as

shown in Figure 8.15 "Critical Path". Durations are indicated in days. The critical path

through these tasks takes at least eight days. Activities on the critical path are shaded.

Figure 8.15 Critical Path

Early Start Dates

Starting dates can be assigned to each activity by doing a forward pass proceeding from left

to right in the network diagram beginning with the project start date. The dates derived by

this method are the early start (ES) dates. The early start date for an activity is the earliest

date the activity can begin. The estimate considers durations and resource availability

calendars. To calculate early start dates, begin with the project start date and assign that

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date as the start date of activities that have no predecessor activities. Follow these steps to

calculate the early start dates of subsequent activities, assuming finish-start relationships:

Add the predecessor activity’s duration to its start date.

Add the lag time or subtract the lead time.

Refer to the resource calendar (or calendars) that applies to the people and equipment

necessary for the activity, and add the number of off-days that the activity would span on

those calendars.

Assign the calculated date as the early start date of the successor activity.

Forward Pass for John’s Move John begins planning his move to Atlanta the same day he accepts the job. The start date in

this example is Monday, November 29, 2010. Tasks 1.1 and 2.1 can both start on that day,

so the early start dates for tasks 1.1 and 2.1 are November 29. John calculates the early

start date for the activities. A partial list is provided below. Compare the figure below and

the figure in the next sidebar. Observe that John is willing to work on weekends, but

activity 2.2.3 is delayed by two days because one of the moving companies did not provide

bids on the weekend. Observe that activity 2.3 has a lead time of one day, but that

relationship is between activity 2.1 and 2.3. The network path from activity 1.3 is longer, so

the lead time with activity 2.1 is not considered in calculating the early start date of 2.3.

Figure 8.16Early Start Dates Determined by a Forward Pass

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Doing this process manually is error prone and time consuming. Fortunately, there are

computer programs to assist in the process, but the project manager must understand the

process well enough to recognize computer errors. Computer software must be combined

with common sense or good judgment.

Float

Float, sometimes called slack, is the amount of time an activity, network path, or project

can be delayed from the early start without changing the completion date of the project.

Total Float

Total float is the difference between the finish date of the last activity on the critical path

and the project completion date. Any delay in an activity on the critical path would reduce

the amount of total float available on the project. A project can also have negative float,

which means the calculated completion date of the last activity is later than the targeted

completion date established at the beginning of the project.

Float in John’s Move The last activity in John’s move has an early start date of December 28 and a duration of

one day. John could start work on Wednesday, December 29. John’s first day at work is

Monday, January 3, so the project has a total float of five days.

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Figure 8.17Total Project Float

Late Start Dates

The next step is to work through the network diagram from right to left beginning with the

mandated completion date, which is a milestone that is set in the project plan. Subtract the

duration of each activity in each path to determine the latest date the activity could begin

and still meet the project completion date. Resource calendars must be considered in the

backward pass as well as the forward pass.

To calculate late start dates, begin with the project completion milestone and assign that

date as the finish date of its predecessor activities. Follow these steps to calculate the late

start dates of predecessor activities, assuming finish-start relationships:

Subtract the predecessor activity’s duration from its late finish date.

Subtract the lag time or add the lead time to the late finish date.

Refer to the resource calendar (or calendars) that applies to the people and equipment

necessary for the activity, and subtract the number of off days that the activity would span

on those calendars.

Assign the calculated date as the late start date of the predecessor activity.

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The difference between the early start date and the late start date for activities on the

critical path is usually the same as the total float, unless the activities are affected by the

resource calendars differently in the forward and backward pass. For example, if a piece of

key equipment is only available for a few days, activities that depend on it have the same

start and finish dates in the forward and backward passes.

Free Float

If activities that are not on the critical path have a difference between their early start date

and their late start date, those activities can be delayed without affecting the project

completion date. The float on those activities is called free float.

K E Y T A K E A W A Y To calculate total project float, begin at the start date and add the duration of each

activity in each possible path through the network diagram, including nonworking

days from the resource calendars, to determine the early project end date. The

longest path through the network is the critical path. The difference between the

early end date and the required completion date of the project is the total project

float, and the start date of each activity is the early start date. To calculate the late

start dates, begin with the required project completion date and work backward,

subtracting the duration of each activity though each possible pathway.

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8.4 Managing the Schedule

L E A R N I N G O B J E C T I V E S 1. Describe methods of tracking and reporting progress.

2. Define resource leveling.

3. Describe methods of accelerating the schedule.

To manage a schedule, the project manager must know how the work is progressing

compared to the master schedule and, if necessary, make changes to keep the project on

time.

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Tracking and Reporting Progress

Tracking the schedule performance involves measuring the work performed against the

work expected to be performed with a given expenditure of resources. Periodic reporting

on the progress of the project provides the project management team with information on

how the project is performing against expectations and to make decisions and corrections.

Accurate measurement of schedule performance requires planning during the early stages

of the project to determine the unit of measure and process for tracking progress.

Reporting Percentage Completed

To determine the percentage of a project that has been completed, the project manager

must determine what to measure. Some percentages are misleading. For example, a project

that has completed 25 percent of the scheduled activities does not mean that the project is

25 percent complete. In our John’s move example, four rooms were to be packed. After the

bedroom was packed, packing was not 25 percent complete. The kitchen contained five

times as many items and required more delicate, time-consuming packing. John estimated

that 40 percent of the items to be packed were in the kitchen, 20 percent in the living room,

20 percent in the bedroom, and the remaining 20 percent in miscellaneous locations. If the

unit of measure for these activities is items packed, the packing is only 20 percent complete

instead of 25 percent if rooms are the unit of measure.

The unit of measure for tracking schedule progress is related to the estimate. If hours of

labor are used as the unit of measure, the percentage of packing is even less because more

time is estimated to pack each item in the kitchen. As the project management team

estimates the duration for each activity, the amount of work to accomplish the tasks is

captured in both resources expended and a unit of measure for tracking progress. The unit

of measure is related to the type of project. On a software development project, the unit of

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measure may be lines of code written. The unit of measure that is chosen can affect the

quality of the work.

Units of Measure on a Programming Project Steve Ballmer of Microsoft recalls early clashes with IBM over the unit of measure used to

determine how much Microsoft would get paid for its work.

In IBM there’s a religion in software that says you have to count K-LOCs, and a K-LOC is a

thousand lines of code. How big a project is it? Oh, it’s sort of a 10 K-LOC project. This is a

20 K-LOCer. And this is 50 K-LOCs. And IBM wanted to sort of make it the religion about

how we got paid. How much money we made off OS/2, how much they did. How many K-

LOCs did you do? And we kept trying to convince them—hey, if we have—a developer’s got

a good idea and he can get something done in 4 K-LOCs instead of 20 K-LOCs, should we

make less money? Because he’s made something smaller and faster, less KLOC. K-LOCs, K-

LOCs, that’s the methodology. Ugh anyway, that always makes my back just crinkle up at

the thought of the whole thing. [1]

In this case, IBM’s insistence on using thousands of lines of code as the unit of measure did

not reward Microsoft for writing smaller code that would run faster. Microsoft and IBM

cancelled their joint project for writing an operating system named OS/2. Microsoft wrote

Windows, and IBM’s OS/2 operating system was not able to compete with it successfully.

On a construction project, a unit of measure may be yards of concrete poured, and on a

training project, the unit of measure may be the class curriculums developed or the

students taught.

Managing Schedules Using Milestones

Milestones provide the opportunity for project management to focus on completing

activities that will have the greatest impact on the schedule. On complex projects, focusing

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on the milestones is useful for communicating important dates to the entire project team.

Project team members can then adjust their efforts to complete the activities connected to

the milestone events.

Many project leaders believe that time lost on early activities can be made up toward the

end of the project. Hard decisions about paying overtime and working weekends are often

delayed until the end of the project when the pressure to complete the project on time

becomes much stronger. Project managers who focus on milestone events create a sense of

urgency to meet the milestone deadlines and spread the urgency to complete the project

over the life of the project. Projects that meet milestone dates are more likely to meet

project completion dates.

Informing Stakeholders

A schedule update is distributed regularly to provide project stakeholders with an

assessment of the progress of the project against the master schedule. This updated

schedule is called thecurrent schedule. The current schedule provides new start and end

dates for all activities and the project. Calculations based on the current schedule may

result in a new critical path and subsequent changes in the project execution plan.

The project team develops an understanding of the project productivity by comparing the

current schedule to the original schedule. If the schedule is behind original estimates, the

project team conducts an assessment of the causes of the schedule slippage and develops a

plan to address the changes to the project. The project management team typically has

several alternatives for addressing changes to the project situation. Selecting the right

alternative requires good information.

Resource Leveling

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The schedule of activities is constrained by the availability of resources. If you apply the

resource calendar to each activity to be sure the people and equipment are available on

those dates, you can still miss an important constraint. If there are several activities that

use a particular person’s time on the same days, that person could end up with too many

activities scheduled for the same days and very little on other days. If key people are

overloaded, the activities to which they are assigned might not be completed on time.

Managing the schedule of activities to ensure that enough resources are available to

complete each task by distributing the work load is calledresource leveling. Activities to

which that person is assigned and that have free float can be delayed to reduce work

overload of key people.

Accelerating the Schedule

The project manager must know how to accelerate a schedule to compensate for

unanticipated events that delay critical activities or to accommodate changes in the project

completion date. Compressing or crashing the schedule are terms used to describe the

various techniques used to shorten the project schedule. Project managers utilize several

techniques to keep projects on schedule.

Contingency Resources

One method of accelerating the schedule is to add activities to the critical path that are

empty or that are optional. If the project is behind schedule, the time can be made up by

dropping these activities. This extra time that is built into the schedule is

called contingency time, buffer, or reserve time.

Reassigning Resources

Activities that are not on the critical path that have free float can be delayed without

delaying the end date of the project if they start by the late start date. Project managers can

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divert some resources from activities with free float to activities on the critical path

without delaying the completion of the project.

Changing Scope

The unit cost of work to be performed on a project is calculated at the beginning of the

project based on the execution strategy of the project to meet the project completion date.

If the project completion date is moved up, then the unit cost of work will likely increase.

Conversely, a project team may be able to save money by extending the project end date.

With more time, the project team may be able to schedule activities in such a way to reduce

their costs. For example, an activity requiring overtime to be paid can now pay the labor at

normal rates, saving the overtime premium. Changing elements of the master schedule

means a change in scope. Scope changes often affect costs and require agreement by the

parties who signed the original scope documents.

Additional Resources

Another option is to allocate funds that can be used to add resources if necessary. Available

resources can be increased by adding overtime to existing resource calendars or by hiring

additional contract workers or renting additional equipment.

Adding Resources to the Dreamliner Project When Boeing sales of the new 878 Dreamliner Airplane exceeded expectations, contractors

who were building the plane were asked to increase production while maintaining all

quality and safety requirements. All contractors involved in the plane production were

affected by this change.

One project team was responsible for developing and delivering training to the new

employees who would be building the fuselage of the Dreamliner. Training for new

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employees had to be complete three months early and the project team developed an

execution strategy to meet the new deadlines. The project had a month of float, so the

project accelerated the schedule by two months. The team authorized overtime from forty

to fifty hours a week for team members working activities on the critical path. The project

team leased additional space and hired contractors to perform selected work packages on

the critical path and delayed the production of library quality documents until after the

critical dates on the project. Authorizing overtime and hiring contractors added a 15

percent cost to the project. Overtime and the procurement of additional contract help was

authorized only for work packages on the critical path because work not on the critical

path would not accelerate the schedule.

A concrete contractor on a construction project may be scheduled to lay one thousand

yards of a building foundation by pouring one hundred yards a day for ten days.

Foundations are on the critical path, and because of rain, the project is three days behind

schedule. The project manager asked the concrete contractor to bring in a second crew and

pour two hundred yards a day, and the work is complete in five days.

Changing Quality

Another option for accelerating the schedule is the changing of the quality specifications of

the product. This is usually done as a scope change.

Making Up Time by Reducing Quality At a midwestern university, a new building was being built, but it was behind schedule. To

speed up the installation of the heating and cooling equipment, it was decided to make the

zones of control larger, which meant that each floor would have fewer points where

temperature was sensed and controlled and fewer air flow control boxes. The contract did

not specify the zone size or how many control points were required on each floor of the

building, so this change did not require a change in scope. As a result, when the sun is

coming in on the south side of the building, those rooms get as much heat or cooling as the

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rooms on the north side, so they are often too hot. If the single temperature controller on

each floor is set to a lower temperature, the rooms on the north side are too cold. The client

for the building did not realize this change had been made until they were in the building

for several months and the project was completed.

K E Y T A K E A W A Y S Progress can be measured by determining the percentage of resources expended,

completion of activities by scheduled dates, milestones achieved, or fraction of

activities accomplished. Standards used to measure progress, particularly when partial

payment to contractors is concerned, should be specified in contract documents.

Resource leveling is reallocating people and equipment to remove periods of overuse

or underuse.

Unplanned delays and costs can be anticipated by including contingency time and

budget amounts where needed to keep the schedule on time. Resource allocation and

resource calendars should be examined to determine if a resource is overcommitted.

Free float can be used to delay noncritical activities that use the same resource to

allocate its time more evenly. If it is necessary to accelerate the schedule, activities

that are not on the critical path can be delayed using their free float and their

resources can be moved to activities on the critical path to complete them sooner.

Contingency resources can be committed to speeding up the activities. If necessary,

the scope can be changed to bring in additional resources or lower the quality.

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[1] Robert X. Cringely, Triumph of the Nerds, June 1996, http://www.pbs.org/nerds/part2.html (accessed July 27, 2009).

8.5 Project Scheduling Software L E A R N I N G O B J E C T I V E S

1. Describe the relationship between the choice of software and project complexity.

2. Identify the features that should be considered when selecting software for project

management.

Low-complexity projects can be managed with lists of activities on paper or by using an

outline in word processing or spreadsheet software. This software is inadequate for

tracking complex projects. Fortunately, there are several dedicated software programs that

keep track of the complex relationships between activities and resources.

Appropriate to Project Complexity

Simple projects can be tracked using general purpose word processing and spreadsheet

software like those available in Microsoft Office or OpenOffice. Medium-complexity projects

benefit from dedicated project management software such as Microsoft Project and

OpenProject. Complex projects require software that can track the interactions of

thousands of tasks and produce sophisticated reports such as Oracle’s P6.

Features

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There are dozens of computer software programs available with a wide range of prices.

Some open source software programs are free, but others cost up to a thousand dollars.

There are several considerations for selecting a project management software besides

price.

Currently Used Software

Use software that is already in use and with which most team members are already

familiar. If software that is used by most team members is appropriate to the complexity of

your project, it is the default choice. It is also valuable to know what software is used by

key vendors or project partners so files can be exchanged electronically in the same format.

Basic Features

Any project management software that is selected must have the ability to track and

display basic features such as the following:

Durations

Relationships

Milestones

Start and end dates

Resource calendars

Graphic displays using Gantt and network charts

Collaboration

Team members should be able to view the project schedule. Some software products

require the use of expensive proprietary software that runs on the company’s server and

that will allow several different team members to use the same schedule and restricts the

use of the software to team members who have access to the company’s computer system.

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Other software products use a server on the Internet that is open to team members and

vendors who have valid passwords.

Advanced Features

For more complex projects, look for advanced features, such as the following:

Issue tracking that tracks problems, actions, and resolutions

Project portfolio management that tracks and compares groups of related projects

Automatic resource leveling and alerts when a resource is overscheduled

Document management feature that tracks contracts, bids, scope changes, and incidents

K E Y T A K E A W A Y S Medium- to high-complexity projects usually require the use of software that is

designed specifically for managing projects.

Features to look for when choosing project management software include (1)

compatibility with existing software at the company or its vendors, (2) basic features

for managing medium-complexity projects, (3) a method for collaboration between

team members, and (4) if needed, advanced features for managing multiple projects.