project management

Module 3: Project Schedule Management (Created by Dr A Cabello, 2020)

Institution: Platform Site: ENGG951 (S221) Engineering Project Management

Book: Module 3: Project Schedule Management (Created by Dr A Cabello, 2020)

Printed by: Dixitkumar Pravinbhai Patel Date: Thursday, 9 September 2021, 5:23 PM

Table of contents

1. Introduction

2. Defining activities 2.1. Case Example 3.1

3. Project Time and Cost Management

4. Activity Sequencing 4.1. Network Computational Processes 4.2. Types of Task Dependencies

5. Estimate Activity Resources

6. Estimate Activity Durations

7. Developing The Project Schedule

8. Schedule Monitoring and Control

9. References

10. Glossary 10.1. How much of detail/decomposing? (Source: Larson & Gray, 2011; p. 142) 10.2. Agile Project Management 10.3. Activity Relationships 10.4. Project Milestones 10.5. Resource Calendar 10.6. Analogous Estimates 10.7. One Point Estimates 10.8. Parametric Estimates 10.9. PERT Estimates 10.10. Reserve Analysis 10.11. Crashing 10.12. Fast Tracking 10.13. Schedule Compression 10.14. Resource Leveling 10.15. Rolling Wave Method 10.16. Critical Chain Method (CCM) 10.17. Schedule Baseline 10.18. Types of Costs 10.19. Accuracy of Estimates 10.20. Human Resource Plan (as used in cost estimating) 10.21. Example for Funding Limit 10.22. Control Accounts 10.23. Activity Sequencing Exercise Part A (Solution) 10.24. Progress Reporting Methods

1. Introduction

The Content in the following Module is aligned to PMBOK Knowledge Area 6: Project Schedule Management.

Project scheduling provides a detailed plan that represents how and when the project will deliver the products, services, and results defined in the project scope and serves as a tool for communication, managing stakeholders’ expectations, and as a basis for performance reporting. The project-specific data, such as the activities, planned dates, durations, resources, dependencies, and constraints, are entered into a scheduling tool to create a schedule model for the project.

TABLE 3.1 Project schedule Management as described in the PMBOK Matrix (SOURCE: PMBOK, 6th Ed)

In the above table, it is evident that when a project manager is undertaking the activity of Project Schedule Management, they are actually conducting sub- activities that are categorised as belonging in the PMBOK "Planning Process Group" and the "Monitoring and Controlling Process Group". Each of these processes are briefly described below.

6.1 Plan Schedule Management - is the process of establishing the policies, procedures, and documentation for planning, developing, managing, executing, and controlling the project schedule. For a detailed explanation students should reference the PMBOK guide p179. In establishing the Project charter, examining enterprise environmental factors and organisational process assets for relevant inputs the project manager has enough information with which to begin the process of scheduling and ultimately produce a schedule management plan.

6.2 Define Activities - is the process of identifying and documenting the specific actions to be performed to produce the project deliverables. Students might recognise this as the previous steps discussed in module 2 related to the establishment of a scope and the creation of a work breakdown structure (WBS).

6.3 Sequence Activities - Is the process of identifying and documenting relationships amongst the project activities. This is the process in which the logical sequence of work to obtain the greatest efficiency for a project is determined.

6.4 Estimate Activity Durations - Is the process of estimating the number of work periods needed to complete individual activities with the estimated resources. This action is made up of three separate steps. The first is estimating the time to complete an activity, then allocating the resources required to complete an activity and finally determining the overall cost of an activity.

6.5 Develop Schedule - Is finally the process of pulling all of these elements together and analysing the activity sequence, the activity durations and the resource requirements for each activity and considering the scheduling constraints to ultimately create a final baseline schedule for the project which can be monitored during execution.

6.6 Control Schedule - Is the process that occurs during the execution of the project where the project manager monitors the status of a project and compares it to the planned baseline to update the project schedule and then uses this information to manage changes to the schedule baseline.

Figure 3.1 may assist you in understanding how many of these processes fit together in the actual practice of planning a project.

FIGURE 3.1 The Project Planning Process

 The first step after initiating the project is to identify the work that needs to be done. This is defined by the Scope & WBS. But in order to sequence the activities together into a “Network” the project manager needs first to identify the activity time frames and the interrelationships between activities. This enables the project manager to build a Project Network diagram that visually depicts these activity interrelationships. Once this is done, resources can be allocated to each activity which may well impact the duration of the project. At this time each activity can be costed to enable the creation of a budget. All of these elements ultimately feed into the master plan.

An important element that must be considered in all of these activities is the element of risk. Each step in the process of conducting this scheduling will identify risks to the project which must be documented. The identification of these risks in turn will in turn impact the final schedule as management strategies are developed to mitigate the more significant risks. The concept of risk management will be addressed in more detail in later modules.

This module is intended to cover the key aspects of NETWORK creation and resource scheduling identified in the process described above and shown in Figure 3.1.

2. Defining activities

A prerequisite for planning time is to identify what needs to be done to deliver specific project outcomes. As such, the activities that need to be completed within a given time frame to achieve a certain objective should be clearly identified and defined, as an essential part of the planning effort.

Figure 3.2: Overview of the process of activity definition

You may recall that in Module 2 we used the term work package to represent the smallest item in a WBS. Well, now it is time to define the activities  further, and estimate the time, cost and resources of the work packages that make up the activities.

How much of the detail is maintained in defining activities, is a judgement call. Usually, it falls within the discretion of the project manager and the project team to achieve a level of detail that is desirable and appropriate for the level of sophistication of the task at hand. Remember that the logic behind defining activities and designing work packages and was breaking down the larger or more complex tasks into manageable smaller units. Figure 3.3 below depicts how a WBS is decomposed to define activities and subtasks or work packages.

Figure 3.3: Decomposing a WBS to identify activities, tasks and subtasks or workpackages

Activities and tasks are usually broken down and defined at an adequate level of detail so that the resource usage can be tracked, the cost per activity can be determined and the progress of the activity can be monitored. These details are contained in the work package (shown in the above diagram as the subtask level). Once activities are defined in this manner, they could also be used for such purposes as the measurement and evaluation of project team members’ performance. For example, if the project manager can identify that an individual has consistently excelled in a particular activity in a project, that individual’s capabilities could be put to the best use in future projects.

In order to define activities with a sufficient degree of clarity and accuracy, one should have a thorough understanding of the work to be completed on the project. The primary source of information used in defining activities is the scope baseline which is commonly documented in a “Detailed Scope Statement”. The scope baseline consists of the scope statement, the WBS and the WBS dictionary. In decomposing a WBS, the project manager may invite experts within the organisation to brainstorm for ideas. The project manager may also use templates, standards and guidelines available within the organisation.

However, a highly prescriptive approach to defining activities may not always be possible, for example, in cases where the scope of work keeps changing or not clear at the initial stages of the project. In such circumstances, a project manager may choose to define activities on the go, which means activities are defined when the work to be conducted on the project gets clearer - this is called the ‘rolling wave’ method of planning and is commonly seen in agile project management.

At the end of the process of defining activities, the project manager should have a list of activities to be completed and may also have supplementary material such as the attributes of those activities. These attributes would include a description about the activity, assumptions, constraints, activity relationships and people responsible for the activity. This activity list can then be used to compile project milestones or significant intermediate delivery points pertaining to the project.

Consider passing this course as a project, and you, of course, are the project manager; what project milestones would you define?

The key milestones in completing a course of study may include: enrolling in the subject by due date; preparatory work such as reviewing course outline and purchasing text books; reviewing content material pertaining to each unit; preparation and completion of assignments and the final exam. You may have identified these milestones in different formats and perhaps in a slightly different order.

The next step in time management is to determine the order in which the defined activities should be completed, i.e. the sequence of activities.

2.1. Case Example 3.1

 Case Example

William Jacobs, a university student, has recently attended a meeting between the project manager and three project engineers, at the local construction firm, ExcellentResults Pty Ltd., William is undergoing an industry placement as part of his degree at UOW.

The meeting was to review the progress of three projects the three project engineers were working on for the past six months. One project was to build concrete posts to support the fences, the other was to fence a farmland using barb wire, and the third project was to build a parapet wall around the premises of a factory. The project management jargon was new to William, because he has only begun his project management course. Amidst an array of abbreviations being exchanged, the project manager asked the project engineers about the health of their projects.

William wondered what was meant by the health of the project, and caught hold of some abbreviations that sounded like CPI and SPI, but did not dare ask anyone what they meant, but listened carefully. It appeared that if both CPI and SPI were above or close to a value of 1, the project engineers were off the hook; however, Trevor, one project engineer, who said his SPI was 0.78, was advised to bring forth his schedule for a group review.

William would learn in the next few lessons at the university that there is much underlying information that feeds into arriving at final values for CPI and SPI. In these online modules we will take you through the process of planning, monitoring and controlling of project time and cost and introduce both time management and cost management knowledge areas. This will assist in developing your understanding of project schedule control and cost control, and calculating values such as CPI and SPI.

Note that CPI stands for cost performance index, while SPI stands for schedule performance index, both of which will be discussed in these online modules and both of which are used in monitoring and controlling the project which is discussed later in this module.

3. Project Time and Cost Management

Completing a project within an agreed timeframe and budget is a key measure of project success. Time and cost management are fundamental aspects of project management and there are a number of tools and techniques available for the purpose of planning, monitoring and controlling project time and cost. Figure 3.4 below shows the relationship between the Project Schedule Management and Project cost Management knowledge areas and the project management process groups involved, as per the PMBOK® Guide.

Figure 3.4: Cost and time management processes vs. project management knowledge areas (Source: PMBOK® Guide, 6th Ed)

In the following sections of this module the key management processes relating to project schedule management are explained. This will then naturally feed into the following module which will deal with Project Cost Management.

You may follow the hyperlinks provided, whenever you would want to explore the new terms, concepts and tools introduced throughout the module.

4. Activity Sequencing

In the process of activity sequencing, the documents that were created in the activity definition process; i.e. activity list, activity attributes and milestones document are consulted along with the scope statement, as well as other standards, procedures, protocols and templates.

Figure 3.5: Overview of the process of activity sequencing

The sequence of activities is usually illustrated using network diagrams. There are two main conventions used in constructing network diagrams: one is known as the activity on node (AON); and the other is known as activity on arrow (AOA). The AON is the most widely used convention and it is also known as the precedence diagraming method (PDM). Some organisations may have customised templates to be used when drawing these diagrams. Larson & Gray (8e; p. 173), specifies the following eight rules, for constructing network diagrams.

1. Networks typically flow from left to right. 2. An activity cannot begin until all preceding connecting activities have been completed. 3. Arrows on the network indicate precedence and flow. Arrows can cross each other. 4. Each activity should have a unique number. 5. An activity ID number must be larger than any numbers that precede it. �. Looping is not allowed. 7. Conditional statements are not allowed. �. When there are multiple start or end activities in a project, a common start node or end node can be used.

(A) A is preceded by nothing

B is preceded by A

C is preceded by B

(B) Y and Z are preceded by X

Y and Z can begin at the same time, if you wish

X is a busty activity

(C) J, K, & L can all begin at the same time, if you wish (they need not occur simultaneously)

Figure 3.6: Notations for AON diagramming (Source: Larson & Gray, 8e; p. 174)

The above figure provides useful notations applicable to the AON method of network diagramming.

A simple network diagram which utilises the above notations is given below.

Figure 3.7: A simple network diagram (Source: Maylor, 2010; p. 138)

At the end of this process, the project manager should have developed a project activity network diagram and updated the relevant project documents as required.

Watch the following VIDEO 3.4.1 which is an extract from a past lecture and which explains the steps in going from a WBS to a simple project Network in a great deal more detail than is available in this module.

Module 3 Lecture Video - Activity Sequencing 

But

All (J, K, L) must be complete before M can begin

M is a merge activity

(D) Z is preceded by X and Y

AA is preceded by X and Y

 ACTIVITY 1

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Question 1. How does the WBS differ from the project network?

 Submit

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Question 2. Why bother creating a WBS? Why not go straight to a project network and forget the WBS?

 Submit

Exercise

It is proposed to extend an existing factory which manufactures steel building products, to install some additional equipment to manufacture steel house frames and to erect a new sales office in the factory building. The activities which make up the project are shown in the table below.

Part A Determine the dependencies between activities from the following information:

i. The new equipment is to go in the existing building and therefore can be delivered and installed simultaneously with the design and construction of the building extension. But, the new equipment is not to be commissioned until the building extension is clad; and

ii. The design and construction of the building extension should follow the order indicated in the table below. Once the extension is clad the new sales office can be put in place.

 Check

AG B CG

D E F

G H I

Part B Draw a precedence diagram using the activity on node method for the project, using the above notations. After you have attempted the drawing, click the button below and compare your answer with the provided solution.

Solution

The solution to the precedence diagram is as follows:

Hide

4.1. Network Computational Processes

The project network is a visual representation of the activities in the right sequence for the project. Assuming that the times for each activity have been calculated and the availability of resources has been determined, this network diagram allows someone who is trying to schedule a project to compute the start and finish times for activities and estimate the total time it will take to complete a project. These computational processes are referred to as forward and backward passes.

Whilst you have not yet covered estimating costs and assigning resources in any detail – assume for the sake of the following exercises that these have already been determined for each activity.

A Forward Pass is used to calculate the earliest times at which an activity can start and the earliest times an activity can finish it can also be used to calculate the expected time for a project.  A Backward Pass is used to calculate how late can an activity start or finish. Having calculated the backward pass it can now be compared to the forward pass to calculate the Slack or Float available in an activity. This in turn can be used to determine the critical path for the project.

The Critical Path is a term is used, to identify the path(s) with the longest duration through the network; if an activity on the path is delayed, the project is delayed the same amount of time. Another important term which is related to the critical path is network sensitivity. The term sensitivity is used to reflect the likelihood of a project's critical path changing once the project is underway. So an insensitive network is one in which the activities involved have a significant amount of slack or float associated with them, whilst a sensitive network would be one in which there is very little slack. In this case if anything were to go wrong in the project which would cause a delay, its much more likely that the critical path will change.

Watch the following video extracts from past lectures which explain these network computational processes, the importance of the critical path and network sensitivity.

Module 3 Lecture Video - Forward Pass

Module 3 Lecture Video - Backward Pass

Module 3 Lecture Video - Determining Slack or Float

 ACTIVITY 2 : Network Computation Exercises

Question 1

A) Draw a project network from the following information. What activity(s) is a burst activity? What activity(s) is a merge activity?

ID Description

A Survey site None 2

Predecessor Time

After drawing your own project network, double check by clicking the button below.

Project Network Diagram

Fill in the the ID for the appropriate activity.

is a Burst Activity.

is a Merge Activity.

 Check

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B) Determine the critical path and calculate the project duration.

 Submit

Question 2

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A Survey site None 2

B Excavate site A 4

C Install power lines B 3

D Install drainage B 5

E Pour foundation C, D 3

ID Description

A Survey site None 2

B Excavate site A 4

C Install power lines B 3

D Install drainage B 5

E Pour foundation C, D 3

Predecessor Time

4.2. Types of Task Dependencies

In the preceding sections you learned how to sequence activities and determine the critical path for a project. These activities were primarily focussed on "Finish - to Start" activity relationships which are the most common. There are in fact four different types of task dependencies.

Finish-to-Start (FS): in which task B cannot start until task A finishes. For example "Building the frame starts after the concrete slab has cured”

As mentioned above, this is the most common scenario and in the absence of any other criteria, all tasks could have this dependency in order to produce a functioning schedule 

Finish-to-Finish (FF): In which, task B cannot finish until task A finishes. For example, “Design prototype cannot finish until all consumer testing is completed”

Start-to-Start: In which, task B cannot start until task A starts. For example “Thermocouple testing cannot start until the furnace fire-up has initiated”

Start-to-Finish: In which the finishing event of task  B (a Successor Activity) is dependent on the starting event of task A (a Predecessor Activity). 

For example, “ Final inspection cannot finish until the client review starts”  or "Task A = Phase out Old Software System (Odyn). Task B = Start using New Software System (Neon), It is assumed that Neon & Odyn cannot be used in parallel. Odyn cannot be phased out until Neon is started."

How these are used in developing a schedule will become more evident when you attempt the MS Project software tutorials in Weeks 4 and 5.

5. Estimate Activity Resources

Once the sequence of activities is established, the next step is to estimate the resources required to complete the activities. Resources will cost money and are not confined to only human resources, but also the machinery, raw material and any other resource(s) required for completing the project.

Figure 3.8: Overview of the process of estimating resources for an activity

The activity list, activity attributes, resource calendars, templates, standards and guidelines may be referred to in this process. In order to arrive at the resource estimates, various estimating methods may also be used; the top down and bottom up approaches described below are two such methods.

Top down approach is used when the work at hand is clear; the organisation may have prior experience in similar work; and where input from experts, templates, standards and guidelines are readily available. The bottom up approach is used when there is no previous experience of similar work and therefore, the work that needs to be conducted has to be gradually sorted out. Table (3.1) below provides some examples of situations where each type is most suited.

Table 3.2: Conditions that help decide when to use top down and bottom up estimates (Source: Larson & Gray, 2021, 8e, p141)

Once satisfactory grounds for estimating resource requirements are established, the activity resources and the resource breakdown structure (RBS) are compiled (see the figure below for an example of RBS), and the project manager will then make an informed judgement to update any other project documents as needed.

Condition Top-Down Estimates Bottom-Up Estimates

Strategic decision making X

Cost and time important X

High uncertainty X

Internal, small project X

Fixed-price contract X

Customer wants details X

Unstable scope X

Figure 3.9: An example of a resource breakdown structure  (Source: Sherrer, 2009; p. 144)

6. Estimate Activity Durations

The next step in time management is to estimate the duration of each activity.

Before a realistic estimate of the duration of an activity can be established, the level of skill and availability of project team members must be determines, as well as other aspects such as working conditions, as they can each affect the duration of an activity. 

Figure 3.10: Overview of the process of estimating activity durations

Estimation of activity durations would, arguably, be one of the most critical and challenging tasks associated with project time management. Any variation in activity duration estimates will not only have a direct impact on task completion dates, but also a cascading effect on the project schedule. 

Information required for estimating activity durations can be drawn from a variety of sources, including the activity list, activity attributes, activity resource requirements, resource calendars, project scope statement, organisational standards, procedures, templates and guidelines. Project managers may also use their expert judgement and verify with technical experts in estimating activity durations. Some popular methods for developing estimates for activities include: analogous, one point, parametric, three point estimates and reserve analysis. Some of these may take a top-down approach while the others take a bottom-up approach. 

The activity durations, when established, should be documented and the relevant project documents should be updated.

We will cover more detail on estimation in later modules. However, you may wish to watch the following video extract from a past lecture as an introduction to this concept of estimation and why accurate estimation is critically important for effective project management. It also introduces you to some variations to the technique used for cost estimations vs time estimation.

Module 3 Lecture Video - Introduction to top down and bottom up estimation techniques.

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In this module, you are being introduced to the concept of estimating resources, time and costs. Cost estimations will be revisited in later modules. However, at this time it is worth introducing the concept of value engineering. Value engineering (VE) or value analysis, is a systematic, organized approach to providing necessary functions in a project at the lowest cost. It promotes improving the value of a project by examining the function of each item or element being estimated and alternate ways to improve the cost/benefit ratio are considered without impacting functionality. This might include a consideration of alternate construction/production methods, alternative designs, or materials that improve the value of the project. Ultimately, a discussion of this technique is outside the scope of this subject but it is certainly a useful tool in the event that an estimate for a project exceeds the limitations placed on the project.

7. Developing The Project Schedule

Once the list of activities has been developed and activity sequences, resource requirements and activity durations have been established, the final step in time planning is to develop the overall project schedule. The project schedule consists of time-phased activities showing resources allocated to each activity, presented in a suitable graphical form such as a Gantt chart or bar chart.

Figure 3.11: Overview of the process of schedule development

In developing the project schedule, outputs generated through the processes mentioned above are brought together. That means the preliminary network diagrams are analysed and the critical path would be established - the critical path analysis will lead to establishing the overall project duration. However, if the scheduled end date of the project does not fall within the desired completion date, the project manager may consider schedule compression methods. Likewise, if a particular resource was found be overloaded, then, re-scheduling of certain activities, taking into account the resource constraints, may be necessary – this may well result in extending the overall project duration. The project manager may also want to make sure that the resource utilisation throughout the project remains as even as possible. This can be achieved through resource levelling.

Schedule compression and Resource levelling will be dealt with in more detail later in this module but for the moment I recommend that you take the time to watch the following video extract from a past lecture that introduces you to Gantt Charts which are an important tool for developing a project schedule and it explains how you can use a Gantt chart to track a project's performance against its baseline.

 Module 3 - An Introduction to Gantt Charts

Schedule compression referred to earlier in this module uses different techniques to achieve a reduction in the time to complete a project. These include fast tracking, crashing and the critical chain method. Watch the following lecture video extracts which explains these three concepts.

Module 3 Lecture Video - Reducing Project Duration Using Fast Tracking and Crashing

Module 3 Lecture Video- The Critical Chain Method (part A) - The Method Explained

Module 3 Lecture Video- The Critical Chain Method (part B) - A Practical Application and Implications

Until a consensus is reached, schedule development may take an iterative route (rolling wave method). This is a process often conducted when applying AGILE project management when the final output of a project or the project design is not known in great detail. The development of the final schedule may also require the application of schedule compression methods such as crashing and fast tracking. An alternative and more advanced method prescribed for ensuring resource availability in a project is the critical chain method and may also be considered in schedule development.

On completion of this process, the project schedule, a schedule baseline and schedule related data would be generated. Other relevant project documents may also be updated as necessary.

 ACTIVITY 3: Reducing Project Duration

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Question 1. What are five common reasons for crashing a project?

 Submit

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p

 ACTIVITY 4: The Critical Chain Method

Snapshot from practice question relating to The Fastest House in the World. Based on the video you have just watched:

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8. Schedule Monitoring and Control

Once a schedule baseline has been established, and the project is underway, the focus should be shifted towards schedule monitoring and control. Schedule changes should be expected and are a reality. Once a change in scope, duration or resource requirements is identified as a result of unforeseen events or as initiated by the client, a formal request for change should be lodged. Once the change request is formally authorised, the existing information on the project management plan, on the work that has been conducted, organisational templates, tools and guidelines should again be reviewed and evaluated together with the existing schedule.

Figure 3.12: Overview of the process of schedule control

The change may be to shorten the project duration, or to add additional activities or because of staff changes or some other unforeseen circumstances. Whatever the reason, established protocols should be followed when changing the schedule. The work that has been currently completed should be evaluated, the needed change should be incorporated, but before finalising the schedule, it is good practice to re-evaluate and level resources. The project manager may decide to administer schedule compression methods and calculate the variance to see if it is acceptable.

Once the above process is completed, a new schedule baseline should be agreed upon and the necessary project documents should be updated - these will include the project management plan and other documents with regard to the change that was just incorporated, i.e. change requests etc.

9. References

Gido, J. and Clements, J.P. (2003), 2 edition, Successful Project Management, Thomson South-Western

Githens, G D. (1998). Rolling Wave Project Planning. Long Beach: PMI Annual Symposium and Congress.

Larson, E.W. and Gray, C.F. (2011), Project Management: The Project Management Process, 5 edition, McGraw Hill

Maylor, H. (2010), Project Management, 4 edition, Prentice Hall

Mulcahy, R. (2011), PMP Exam Prep, 7 edition, RMC Publications, Inc,

Project Management Institute (2008), A Guide to the Project Management Body of Knowledge

Sherrer J.A.(2009), Project Management Road Trip for the Project Management Professional

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10. Glossary

Module 3: Supplementary Information

10.1. How much of detail/decomposing? (Source: Larson & Gray, 2011; p. 142)

Case snippet 3.1A: How much of detail/decomposing? (Source: Larson & Gray, 2011; p. 142)

10.2. Agile Project Management

A term commonly associated with present day project management, agile project management is seen by many as the answer to managing volatility in projects.  Agile project management relies on incremental, iterative development cycles to complete projects (Larson & Gray, 2011; p. 583). It should be noted that the term, Agile is generic, used to address multiple agile methods. Some of the popular agile methods include Scrum, Extreme Programming (XP), Rational Unified Process (RUP), Dynamic Systems Development Method (DSDM) and Rapid Product Development (RPD). Agile methods stand on the following principles: focus on customer value, iterative and incremental delivery, experimentation and adaptation, self-organization and continuous improvement (Larson & Gray, 2011).

However, in order for agile project management to successfully meet the targets, the stakeholders involved in projects, which include an organisation’s top managers, project managers, team members and the customers are expected to be able to cope with rapid change. The changes in the project environment may be associated with requirements, technology, the planned sequence of events, etc.

Refer to your text Larson & Gray (2011), Chapter 17 for more information on agile project management.

10.3. Activity Relationships

Four types of activity relationships are explained in project management literature. These relationships are best explained with examples.

Finish-to-Start relationship

This is the most widely used relationship; it implies that predecessor activity needs to be completed in order for the successor activity to start. An example can be taken from a project undertaken to build a robot. A situation where the design specifications need to be completed in order for the programming to start could be identified with the finish to start relationship.

Finish-to-Finish relationship

Implies that the successor, cannot be completed until the predecessor activity is completed. Take the example of a road construction project, until the complete route is dug and prepared, the tar layering of the road cannot be completed.

Start-to-start relationship

In this type of relationship the successor activity may start when predecessor activity starts.  Consider an engineering project where the documentation of the requirements could start as soon as the discussions with the customer are initiated.

Start-to-finish relationship

This type of relationship implies that in order for the successor activity to be completed the predecessor activity needs to start. Think of a situation where a legacy system is being phased out, the predecessor activity is the new system which is being introduced, in such a case the legacy system cannot be taken off until the new system has started; because, any down time may be undesirable. 

An illustration of the relationships discussed above is given below. Note that for all of the following illustrations activity B is the successor.

Figure 3.1A: Activity relationships (Source: Adapted from Sherrer, 2009; pp. 136-137)

10.4. Project Milestones

Milestones on a project can be interpreted as pointers on a project schedule. These pointers represent important events in the project schedule, for example, ‘end of requirements gathering’ or ‘completion of the design phase’ of a project. Milestones, unlike activities, do not consume time on the project schedule, but as described above, is an important point in time during the duration of the project. Milestones can be used as instances for reviewing and communicating the progress of the project to key stakeholders or as an opportunity to celebrate an achievement so as to motivate team members; example: throw a party for the project team to reflect on and celebrate the successful completion of the design phase of a project.

10.5. Resource Calendar

This document illustrates the engagements and availability of a resource, be it human, machinery or other. Consider this example for further clarification: BridgesrUs is an engineering company that specialises in designing and building bridges. The company has just been requested to submit a project proposal for a new project, within two weeks, and their project management office is assessing the availability of the Company’s most experienced design engineer who usually oversees the preparation of new designs. However, the resource calendar indicates that he is currently engaged with another project and won’t be available for three more weeks. Hence, another option needs to be considered: for example, assigning another design engineer to the new job with provisions for a final review undertaken by the lead design engineer; or splitting the work of the current job undertaken by the lead engineer so that part of that work can be off-loaded to a another design engineer, allowing the lead engineer to oversee the design work associated with the new project on a part time basis. The research calendar, as explained, is the document that records the engagements and availability of resources, and as such, is a valuable reference that can be used in this type of situations.

10.6. Analogous Estimates

This type of estimate takes into consideration expert judgements and historical data. Analogous estimates could also be called a best guess, yet, is based on some facts and not entirely superficial. An example is, if a particular activity from a past project(s) took a month, the experts are likely to estimate the same duration for a similar activity in the current project. However, circumstances may have changed, thereby, what was a probable estimate for a previous project may not be viable on the current project. Therefore, there are some risks involved with this method.

10.7. One Point Estimates

With this method, the estimator would submit one estimate for an activity and the estimator may not have a proper understanding of the work that needs to be conducted. Therefore, it is likely that the estimator would unnecessarily add extra padding (i.e. unjustifiable add-ons) to the estimate, which will expand the duration or cost depending which is being estimated. Therefore, there are negative prejudices around this type of estimate.

10.8. Parametric Estimates

Input for parametric estimates can come from historical data, industry standards and the likes. Some examples of estimates using parametric estimating may be listed as: number of days taken for an installation of a computer, time taken to fence a square meter of land, time taken for tiling a square foot of floor and so on.

Parametric estimates could be evolved to map the relations between two variables; it could be the time and no of tiles laid, or the time and no of computer installations done. Therefore, if relationships between variables are discovered they could be used for future project estimating.

Another factor that could be used in parametric estimating is the learning curve; as the term implies, when the same activity is performed repetitively, the time taken reduces, until a plateau is reached. Depending on where a particular organisation is on the learning curve for a particular type of activity, a suitable value could be selected for estimating

10.9. PERT Estimates

Another type of estimate is the program evaluation and review technique (PERT). This allows placing an estimate as a range, instead of a single value. The rationale here is that most projects do not go according to plan and therefore, a single estimate may be a hard target to meet and is considered an improbable estimate. Therefore, PERT brings up a 3 point estimate. The variables used are, a pessimistic value, the most likely value and an optimistic value.

This method will be discussed in greater detail when discussing RISK.

10.10. Reserve Analysis

Reserves are applicable to both time and cost estimates and are, basically, spare time or cost, that may be allocated as fall back in case of any schedule or cost mishaps. Two types of reserves, contingency reserve and management reserve are briefly explained below. 

Contingency reserve is the additional time/cost allocated as responses to already identified risks. Management reserves are allocated for any unforseen risks. The authority to release this type of reserves lies with the top management. Management reserves may be calculated based on lessons learnt on similar projects conducted previously, or based on the judgement of experienced project managers and subject experts.

10.11. Crashing

In order to compress the project schedule, more resources are applied to the project; however, this has to be meticulously navigated. Over application of resources has proven to be a project management hazard, especially when it comes to human resources. However, this method can be successfully utilised after weighing the pros and cons.

10.12. Fast Tracking

In this schedule compression method, multiple activities that were sequentially organised are now conducted in parallel while respecting the technical constraints, again, just like in crashing, careful consideration should be given to determine which activities could be conducted in parallel.

10.13. Schedule Compression

Schedule compression is undertaken with a view to reduce the project duration; there are two commonly used methods known as crashing and fast tracking.

10.14. Resource Leveling

This is a mechanism to achieve an even distribution of resources over the duration of the project, i.e. if there is an uneven fluctuation of resource utilization, this approach may be used to adjust resource levels. Currently there are software tools such as Microsoft Project that would indicate when resource leveling is required.

It is worth noting a distinction in terminology at this point. When resource leveling is conducted within given time constraints (ie the Project is Time Constrained) it can be referred to as Resource SMOOTHING. By extension of this definition the term Levelling then generally applies when projects are NOT time-constrained (ie they are Resource-constrained) and the process of leveling may well extend the project duration.

10.15. Rolling Wave Method

When the final project design is not known in great detail this can cause a number of scheduling difficulties and lead to scope creep if not carefully managed. Agile project management techniques such as the rolling wave method are very useful in this type of situation where the output specification or scope is continuously developed through a series of incremental iterations over time. Iterations are short time frames (“time boxes”) that typically last from one to four weeks. The goal of each iteration is to develop a workable product that satisfies one or more desired product features.

At the end of each iteration, stakeholders and customers review progress and re-evaluate priorities to ensure alignment with customer needs and company goals. Adjustments are made and a different iterative cycle begins. Each new iteration includes the work of the previous iterations and adds new capabilities to the evolving product (see the figure below) to ultimately produce a the final product.

FIGURE 3.X The growth of the detail listed in a WBS in the rolling Wave method

SOURCE: Githens 1998

This is covered quite effectively in your textbook in the Snapshot from Practice 15.1: IDEO: Masters of Design for an example of iterative development in action.

10.16. Critical Chain Method (CCM)

his method is known to assist in managing the variability in duration estimates resulting from risks associated with resource availability on a project. With this method, most important activities are identified, noting that these activities do not necessarily have to be sequential.  This method takes into account both activity and resource dependencies and calculates activities to occur as late as possible, yet not interrupting the end date. Buffers are introduced to cushion the impact of risks at the end of work packages (rather that at the activity level).  The figure below illustrates these buffer types. Refer Sherrer (2009), chapter on time management, from the suggested supplementary reading list for further details.

SOURCE: PMI, PMBOK Guide 5th Edition, Figure 6-19. Example of Critical Chain Method

10.17. Schedule Baseline

The schedule baseline is the project schedule that has been agreed upon by all the stakeholders involved in the project. Changes may be needed on the schedule baseline for a variety of reasons, these could be due to additional requirements, unexpected staff turnover, team members falling sick, breakdown of equipment and so on.  Changes to the schedule should be carefully evaluated and necessary change control should be carried out. Once change is incorporated and agreed upon, the revised schedule will become the schedule baseline.

10.18. Types of Costs

Figure 3.20A: Type of costs (Source: Sherrer, 2009; p. 193)

Direct costs

As the term implies, are costs directly related to the project. Some examples for direct costs are labour, training, machinery and licensing.

Indirect Costs

These are types of costs that are consumed partly by the project, and partly by the rest of the organisation – examples are rent, stationary, print and copy facilities.

Variable costs

As the term suggests the costs vary. The variance may depend on external factors such as price of fuel or internal factors such as raw material needed for the project.

Fixed Costs

These types of costs are usually stable for the duration of the project; an example is the fixed rates promised for the employees for the duration of the project.

10.19. Accuracy of Estimates

The accuracy of estimates used in project time and cost management will be based on the information acquired on the project activities and supporting information. When the project requirements are not very clear, it is difficult to estimate with a high precision. There are alternative estimating methods, which allow estimating with different degrees of precision and are usually conducted at different project phases.

Rough order of magnitude

Usually estimated as a response to the request for project proposal or at project initiation. The range of precision is acceptable at +-50%. These estimates are calculated based on initial customer requirements that are communicated or using very high level documents, which lack the details to improve the precision of the estimate.

Budget estimate

These are estimates that are developed during project planning and may have an acceptable range of precision between -10 to +25%. These estimates are usually conducted once the contract of work has been offered. Therefore, more information is available, and as a result the precision of the estimate will improve.

Definitive estimate

Is compiled as part of rolling-wave planning, when the project progresses, and when the requirements become clearer, the precision would improve. The detailed project and customer documents are also readily available during the execution of the project. Commonly accepted range of precision for this type of estimate is between -10 and +10%.

10.20. Human Resource Plan (as used in cost estimating)

This document will be discussed in detail in a separate module. For the time being keep in mind that labour rates should be referred to from this document when estimating. There may be intricacies with these rates as they may differ according to the level of experience and as per the time of work – i.e. normal hours or the weekend.   Also referred to from this document are the costs for reward systems in the organisation, these costs should be integrated in to the cost estimates.

10.21. Example for Funding Limit

As an example, consider a particular machine which needs replacement parts for uninterrupted production, and the organisation fails to provide the funds required to acquire some parts for an urgent repair job due to lack of available funds or other cash flow problems. Therefore, the repair activities needed to restore the machine cannot take place, and will need to be shifted to be done later in the schedule. During such times, the project manager will need to liaise with the organisation, either for an alternative technical solution or to shift time and cost of the project delivery. More importantly, project managers should consider the organisations funding limits or commitments as part of budgeting deliberations.

10.22. Control Accounts

Control accounts are known as intermediate levels on the WBS where scope, cost, time and resource information may be summarised to measure the project performance.

10.23. Activity Sequencing Exercise Part A (Solution)

Below is the Solution to the Drag and drop exercise for Activity Sequencing Part A. 

ID Activity Duration

(working days) What are the

precedences?

A Order and take delivery of new equipment 15  

B Design building extension 10  

C Prepare site and excavate foundations 7 B

D Pour foundations and concrete slab floor 15 C

E Erect frame for building extension 8 D

F Clad building extension 5 E

G Locate new sales office in building extension 8 F

H Install equipment 9 A

I Commission equipment 5 F

10.24. Progress Reporting Methods

Three methods are introduced in this module, they are as follows:

50/50 rule  Reported as 50% completed when activity starts, then, once completed, is reported as the remaining 50% is completed.

20/80 rule Reported as 20% completed when activity starts, then, once completed, is reported as the remaining 80% is also completed.

0/100 rule No credit is given for partial completion, once the activity is completed, is reported as 100% of the work was completed.

Refer the case snippet 3.5A also:

Case snippet 3.5A: (Source: Larson & Gray, 2011; p. 479)