Work Breakdown Structure and Gantt Charts

Overview

Overview

The project schedule is one of the triple project constraints besides scope and cost (budget). A project manager is responsible for planning, developing, managing, monitoring, and controlling the project schedule to ensure that project objectives can be achieved, and project outcomes can be delivered to the client and customers on time. Effective schedule management is integral to overall project success. The objective is to create a schedule that effectively and efficiently uses allocated resources to complete the project in the shortest amount of time possible. In order to develop a schedule, we first need to create a plan that will guide us during the project. Afterward, we should define the activities based on the WBS, sequence them in the right order, estimate the time it will take to complete these activities, and develop a schedule by creating a network diagram and Gantt chart.

Source: Abdullah Oguz, https://pressbooks.ulib.csuohio.edu/project-management-navigating-the-complexity/chapter/7-0-learning-objectives-overview/
This work is licensed under a Creative Commons Attribution 4.0 License.

Project Schedule Management Plan

As described, project planning is at the heart of the project life cycle and tells everyone involved where we are going and how we are going to get there. It involves creating a set of plans to help guide our team through the implementation and closure phases of the project. The project schedule management plan is one of the sub-plans of our overall project plan. It provides the guidelines to project managers on how to develop a project schedule by defining and sequencing project activities and milestones, and by estimating activity durations. It is the process of establishing the policies, procedures, and documentation for planning, developing, managing, executing, and controlling the project schedule.

A project schedule management plan can consist of the following:

• Unit of measurement
  • Work hours, days, weeks, months
  • Daily working hours and shifts
  • Weekends and/or off-days
  • Local, national, and federal holidays
• Creation of the activity list and attributes
  • Describe how activities and their attributes will be defined, and who will be involved in this process.
• Level of accuracy
  • Acceptable range to ensure realistic activity duration estimates
  • Evaluation of the impact of risks on the overall project duration and each individual activity durations based on the project risk management plan
  • Methods describing how the schedule contingencies will be assessed.
• Activity duration estimates
  • Estimation methods (e.g., analogous, parametric, three-point, bottom-up)
• Methods, tools, and software utilized to develop, manage, and monitor project schedule
  • Specify the organization's procedures, policies, and resource calendars if they should be utilized.
  • Methods and tools such as Gantt Chart, WBS, project baseline, master and milestone schedule, Earned Value Management, and critical path method
  • Software such as Microsoft Project Professional, Excel, Visio, and Jira (for Kanban and Scrum), and online collaboration tools such as Monday, Trello, and Basecamp.
• Rules and concepts to sequence activities and create an activity network diagram
  • Critical path method (Forward pass, backward pass, slacks)
  • Critical chain method
  • Predecessor dependencies (e.g., finish-to-start, start-to-start)
• Rules for monitoring schedule performance
  • Earned Value Management (EVM)
  • Control thresholds for deviations from the parameters in the schedule baseline
  • Using software such as Microsoft Project
• Reporting formats
  • Reporting formats and frequency should be in alignment with other project plans.
• Approval of the schedule baseline
  • Who will be responsible for preparation and control?
  • Who will approve the schedule baseline?

Defining Activities

In line with the project schedule management plan, we should start scheduling the whole project by defining activities based on the WBS (Work Breakdown Structure). The activity definition process is a further breakdown of the work package elements of the WBS. It documents the specific activities needed to fulfill the deliverables detailed in the WBS. These activities are not the deliverables themselves but the individual units of work that must be completed to fulfill the deliverables. Activity definition uses everything we already know about the project to divide the work into activities that can be estimated. We might want to look at all the lessons learned from similar projects our organization has done to get a good idea of what you need to do on the current one.

Detailed planning begins by identifying all the tasks to be completed. The project team begins by reviewing the scope of the project which is found in the project scope statement (predictive/waterfall projects) or the product backlog. A WBS allows the team to have a visual representation of the forthcoming work. As discussed, the WBS is a powerful planning tool. By breaking the project down into smaller, more manageable components, the WBS assists project managers in identifying the specific tasks. The team then determines how long it will take to complete the required tasks.

Expert judgment from project team members with prior experience and from stakeholders that can be consulted can help us define activities while developing project scope statements and WBS. If we are asked to manage a project in a new domain, we could use subject matter experts in that particular field to help define tasks so we can understand what activities are going to be involved. We may want to create an activity list and then have the expert review it and suggest changes. Alternatively, we could involve the experts from the very beginning. 

Sometimes we start a project without knowing a lot about the work that we will be doing later. Rolling-wave planning lets us plan and schedules only the portion that we know enough about to plan well. When we don't know enough about a project, we can use placeholders for the unknown portions until we know more. These are extra items that are put at high levels in the WBS to allow us to plan for the unknown.

When we identify activities for the work packages, we can detail the activities in a project activity list which is a list of everything that needs to be done to complete the project, including all the activities that must be accomplished to deliver each work package with activity attributes. This list can consist of, but is not limited to:

1. Activity identifier
2. WBS number
3. Activity title
4. Scope of Work
5. The person responsible (RACI chart can be used).
6. Related activities
   1. Higher level activities (WBS number)
   2. Lower level activities (WBS number)
   3. Predecessors (including dependencies, that are FS, FF, SF, SS)
   4. Successors (including dependencies, that are FS, FF, SF, SS)
7. Resource requirements
8. Activity location
9. Level of effort required
10. Activity assumptions
11. Activity constraints

The example in Table 7.1 is based on the project charter we developed (Case Study 3.1: Project Charter of Grocery LLC's Mobile-Commerce Project), and the WBS we developed (Case Study 4.1: WBS of Grocery LLC's M-Commerce Project). In Table 7.1, we focus on Activity 1.3 "Preparation of Project Charter" in the WBS. Under Activity 1.3, we determined six activities that can serve as the lowest level of activities, which are work packages.

We can explain each column available in Table 7.1 as below:

Activity Identifier: Once the WBS is created for the project, the list of activities required to complete each work package needs to be developed by the project team. Each activity then needs to be assigned an Activity ID, which is placed in this column. The activity ID serves as a reference identification number during planning, developing, and controlling the project schedule.

Activity List: The name/unique label for the activity (in brief) is placed in this column.

Scope of Work: The description of work required to be done to complete the activity is placed in this column (in as much detail as possible).

Person Responsible: One person or more than one who will be responsible for delivering the activity must be mentioned in this column. It is always good to have a primary and an alternate team member assigned to this responsibility.

Estimating Activity Durations

Creating an Activity Network Diagram

After we define the activities and estimate their duration, we are ready to create an activity network diagram which is a graphical representation of the logical relationship (i.e., dependencies) among the project activities. Duration estimation can also accompany the creation of an activity network. The process can be iterative, and the project team can move back and forth to refine the activities, durations, and their relationships with other activities.

Activities are carried out in order. Therefore, they have predecessors and successors. They have logical relationships or dependencies which show the sequence in which the activities are to be performed. There are four relationships between activities, which can be indicated as "Finish-to-Start" (FS), "Finish-to-Finish" (FF), "Start-to-Start" (SS), and "Start-to-Finish" (SF). The most common relationship is Finish-to-Start at which we start a successor activity once we finish the predecessor activity. Microsoft Project also uses FS as the default relationship. In the MS Project tutorial below, this topic has been also discussed. A start-to-Finish relationship is very rarely used.

Showing the activities in rectangles or circles, and their relationships (dependencies) as arrows is called a precedence diagramming method (PDM). This kind of diagram is also called an activity-on-node (AON) diagram (Figure 7.1). Another way to show how tasks relate is with the activity-on-arrow (AOA) diagram (Figure 7.1). AOA diagram is traditionally drawn using circles as the nodes, representing the beginning and ending points, and the arrows representing activities. AON is more commonly used and is supported by all project management programs. In this textbook, as is also used by PMBOK Guide Sixth Edition, we are using AON diagrams for creating activity network diagrams. Although we used circles in Figure 7.1 for AON, the most common implementation is to use rectangles. Microsoft Project uses rectangles as well.

Logical Relationships / Dependencies

As explained above, four logical relationships can be used in the precedence diagraming method while creating activity network diagrams. Besides these relationships, we will also discuss lags and leads.

Finish-to-Start (FS) Relationship

In this relationship, a predecessor activity should be finished in order to start the successor activity. This is the most common relationship between activities. As seen in Figure 7.2, Activity A must be finished to start Project B.

Examples:

• We need to assemble all hardware and network components of a laptop (predecessor) to install the operating system on this laptop (successor).
• We must finish cooking all our meals (predecessor) to start serving them in the dinner (successor).
• We should finish packing all the luggage to start driving to the airport for the holiday.

Lag

A lag is the amount of time a successor activity can be delayed with respect to a predecessor activity. Consider that we should paint one room in our house. We need to apply plaster to walls first (predecessor). When the walls dry, we can paint them (successor). It is an FS relationship. However, we need to wait for two days for the walls to dry. This causes a two-day delay between two activities which is called a lag (Figure 7.3).

Lead

A lead is the opposite of a lag. A lead is the amount of time a successor activity can be advanced with respect to a predecessor activity. In Figure 7.4, Activity B (successor) can start three days before Activity A (predecessor) finishes. For example, in the project, we should elicit the requirements of stakeholders first. Then, we can start designing the product based on the requirements. If we have ten stakeholder groups, and five of them are key stakeholders, we can start the design before we finish all the elicitation.

Finish-to-Finish (FF) Relationship

In this relationship, we cannot finish a successor activity (Activity B) if we don't finish a predecessor activity (Activity A). Therefore, Activity A must be finished to ensure that we can finish Activity B as well (Figure 7.5). These tasks can be carried out in parallel. It is common to have a lag between the predecessor and successor.

Examples:

• We are writing a new textbook, and it has 15 chapters. When we finish writing, we can complete the book.
• The contractor is finishing the installation of gas lines and plumbing in our new house (predecessor – Activity A). Another contractor who will install the kitchen appliances can finish the installation of these appliances (successor – Activity B) when gas lines and plumbing are done. The second contractor will finish the installation of appliances five days after the predecessor activity is completed. So, there is a lag of five days (Figure 7.5).

Start-to-Start (SS) Relationship

In this relationship, a successor activity (B) cannot start until we start the predecessor activity (A). Like a finish-to-finish relationship, it is possible to see a lag between these two activities. In Figure 7.6, the relationship on the right illustrates a 5-day lag. Activity B can start five days after Activity B starts.

Examples:

• When developers start coding in a software project, testers may not need to wait until they finish all the coding. They can start testing after the coding starts. However, they may need to wait for several hours or days to start testing since some of the coding should be done so that the testers have an adequate number of lines to test. This delay is named "lag" as explained above and also in the "Finish-to-Finish" relationship.
• We are drafting a user manual for our product (predecessor). This manual must be also reviewed to make it ready for publishing (successor). In order to start this review, we should start drafting the manual.

Start-to-Finish (SF) Relationship

This is the rarest relationship between project activities. Activity B (successor) cannot finish until Activity A (predecessor) activity has started (Figure 7.7). Consider that we developed a new order processing software. In the meantime, we still need to use the current software not to cause any interruptions in our operations. Activity A is "Shutting down the current software" while Activity B is "Making the new software operational". We can finish Activity B when we start Activity A.

Exercise to Create an Activity Network Diagram

Our exercise to create an activity network diagram starts with Table 7.4 below. We are assuming that all the dependencies are finish-to-start, and there are no lags or leads in this exercise. We will add other types of dependencies as well as lags and leads in the 7.6 Microsoft Project Professional tutorial.

We are using rectangular nodes for each activity with labels on them. Different software programs can be utilized to create these nodes. In this exercise, we are using Microsoft Visio. When we click "New" and search "PERT Chart" on Visio, we can select "PERT Chart" to open a new sheet. PERT stands for "Program Evaluation Review Technique". It was developed by Booz-Allen and Hamilton as part of the United States Navy's Polaris missile submarine program. PERT is a method for analyzing the tasks involved in completing a project, especially the time needed to complete each task, the dependencies among tasks, and the minimum time needed to complete the total project. Another method, CPM, the critical path method was developed in a joint venture by DuPont Corporation and Remington Rand Corporation for managing plant maintenance projects. The critical path determines the float, or schedule flexibility, for each activity by calculating the earliest start date, earliest finish date, latest start date, and latest finish date for each activity. This will be discussed in detail in the following sections (7.4.3 and 7.4.4). Rather than dealing with both methods separately, project managers use these methods together as they have been treated as a single method over time.

On Microsoft Visio, from PERT Chart Shapes, we drag PERT 1 shape (node) to the blank page. Activities are named as tasks here as is the case with Microsoft Project. We can choose the black color to fill and make the text white color for a good contrast. We can copy this shape, and paste it as needed. In our exercise, we have 13 nodes in total.

An activity node includes the labels as seen in Figure 7.8.

• Early Start (ES): The earliest time we can start an activity.
• Duration: How long it takes to finish all the tasks in an activity. It can be hours, days, weeks, or months.
• Early Finish (EF): The earliest time we can finish an activity.
• Late Start (LS): The latest time we can start an activity. Some activities may have some flexibilities (slacks or floats) that allow us to have some delay to start without affecting the overall project duration and other activities.
• Late Finish (LF): The latest time we can finish an activity. Based on the slacks (floats), we can finish an activity later than its scheduled completion time.
• Slack (Float): It is the difference between LS and ES, or between LF and EF. Both subtractions generate the same result.

In order to connect nodes, we can drag a line connector to the Visio page and connect two activities (Figure 7.9).

Figure 7.9. Connecting a Predecessor to its Successor (FS dependency)

We should place each activity node on the diagram by adhering to their precedence relationships with other activities (Table 7.4). After we connect all the nodes, we can type the duration for each activity as can be seen in Figure 7.10. All other parts in the nodes are zero for now. Besides, as all the dependencies are finish-to-start, the arrows (connectors) start from the right side of a predecessor activity and finish on the left side of a successor activity. For instance, when we finish Activity A, we can start both Activity C and Activity D. When we finish both, we can start Activity F.

Forward Pass:

Now, we can start with a forward pass to determine the early start and early finish dates, and on the last activity, the overall time to finish the whole project. It is an additive move through the network from start to finish.

1. For two starting activities (A and B), ES is marked zero, which means that it is the very first day of the project (Figure 7.11).

2. We add ES to the duration for each activity to find EF. For A, EF is (0+1) = 1 week, and for B, it is (0+2) = 2 weeks. It means that we can finish A at the end of the first week, and finish B at the end of the second week (Figure 7.11).
3. Then, we carry the EF time to the nodes immediately succeeding the recently completed nodes (predecessors). C and D inherit 1 (EF) from A, and it becomes ES for both successor activities. For E, we pass 2 (EF for B) to E as the ES time. Then, we add new ES times to the duration of activities to find the EF for new successors (Figure 7.12).

4. At a merge point, as is the case when C and D merge at F, we pass the highest EF time of predecessors (C and D) to the successor activity (F) (Figure 7.13). EF time of D becomes ES time for F.

5. When the forward pass is done, we can generate all ES and EF times for all the activities. The EF of the last activity (M) gives us the overall duration of the project which is 15 weeks (Figure 7.14).

Backward Pass

Before starting the backward pass process, we should explain the critical path which 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. Therefore, we can 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 we will explain below, slack will be zero for all the activities on the critical path.

After we complete the forward pass process for all the activities, we can start backward pass by moving from the last activity to the starting activities. It is a subtractive move through the network from finish to the start. In our exercise, the last activity is M with a one-week duration, an ES of 14 weeks, and an EF of 15 weeks which also indicates the overall duration of the project.

1. Late Finish (LF) for the last activity M is passed from EF (15 weeks). Then, we subtract LF from the activity duration to find the Late Start (LS). It is (15-1) = 14 weeks (Figure 7.15).

2. Now, it is possible to compute slacks for each activity. It is the difference between LS and ES, or between LF and EF. Both calculations will generate the same result. For Activity M, it is (14-14) or (15-15), which is zero. Therefore, there are no slacks for this activity. We don't have any flexibility for this activity. We cannot have any delays to start the activity or to finish it. The activities where slack is zero are critical.
3. Then, we carry back the LS time to the nodes immediately preceding the successor node. K and L inherit 14 (LS) from M, and it becomes LF for both predecessor activities. Then, we subtract LF times from the duration of activities to find the LS for these predecessors (Figure 7.16). The slack for L is (10-10) or (14-14), which is zero. Therefore, L is also a critical activity. The slack for K is (11-8) or (14-11), which is 3. It means that we can wait for an additional three weeks to start K because we need to wait until week 14.

Figure 7.16: Passing LS times to successors as LF times

4. At a burst point, as is the case when G is followed by two successors, H and I, we pass the lowest LS time of successors (H and I) to the predecessor activity G as its LF time. Therefore, 6 becomes the LF for Activity G (Figure 7.17).

5. When the backward pass is done for all the activities, we can generate all LS and LF times as well as slack times for all of them (Figure 7.18). Thus, we can determine the critical path where the total slack is zero.

The critical path of this project is B – E – G – I – L – M. It is also the longest path. We need to start and finish all these six activities on their scheduled time not to cause any delay in the overall project. Non-critical paths are:

1. A – C – F – J – K – M: 1+2+2+1+3+1=10 weeks
2. A – D – F – J – K – M: 1+4+2+1+3+1=12 weeks
3. B – E – G – H – K – M: 2+1+3+1+3+1=11 weeks

We should always keep in mind that the WBS is not a schedule, but it is the basis for it. The network diagram is a schedule but is used primarily to identify key scheduling information that ultimately goes into user-friendly schedule formats, such as milestone and Gantt charts. The network diagram provides important information to the project team. It provides information about how the tasks are related, where the risk points are in the schedule, how long it will take as currently planned to finish the project, and when each task needs to begin and end.

Schedules must be communicated to project stakeholders. Generally speaking, stakeholders want to know when the work will be completed. Once the completion date is determined, it is important to confirm whether this date can meet the expectations of the stakeholders, in particular the project sponsor, and internal or external clients. Once timeline commitments have been made, stakeholders must be kept up to date on any delays that will cause deviation from the agreed-upon schedule.

Forward Pass

Now, we can start with a forward pass to determine the early start and early finish dates, and on the last activity, the overall time to finish the whole project. It is an additive move through the network from start to finish.

1. For two starting activities (A and B), ES is marked zero, which means that it is the very first day of the project (Figure 7.11).

2. We add ES to the duration for each activity to find EF. For A, EF is (0+1) = 1 week, and for B, it is (0+2) = 2 weeks. It means that we can finish A at the end of the first week, and finish B at the end of the second week (Figure 7.11).
3. Then, we carry the EF time to the nodes immediately succeeding the recently completed nodes (predecessors). C and D inherit 1 (EF) from A, and it becomes ES for both successor activities. For E, we pass 2 (EF for B) to E as the ES time. Then, we add new ES times to the duration of activities to find the EF for new successors (Figure 7.12).

4. At a merge point, as is the case when C and D merge at F, we pass the highest EF time of predecessors (C and D) to the successor activity (F) (Figure 7.13). EF time of D becomes ES time for F.

5. When the forward pass is done, we can generate all ES and EF times for all the activities. The EF of the last activity (M) gives us the overall duration of the project which is 15 weeks (Figure 7.14).

Backward Pass

Before starting the backward pass process, we should explain the critical path which 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. Therefore, we can 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 we will explain below, slack will be zero for all the activities on the critical path.

After we complete the forward pass process for all the activities, we can start backward pass by moving from the last activity to the starting activities. It is a subtractive move through the network from finish to the start. In our exercise, the last activity is M with a one-week duration, an ES of 14 weeks, and an EF of 15 weeks which also indicates the overall duration of the project.

1. Late Finish (LF) for the last activity M is passed from EF (15 weeks). Then, we subtract LF from the activity duration to find the Late Start (LS). It is (15-1) = 14 weeks (Figure 7.15).

2. Now, it is possible to compute slacks for each activity. It is the difference between LS and ES, or between LF and EF. Both calculations will generate the same result. For Activity M, it is (14-14) or (15-15), which is zero. Therefore, there are no slacks for this activity. We don't have any flexibility for this activity. We cannot have any delays to start the activity or to finish it. The activities where slack is zero are critical.
3. Then, we carry back the LS time to the nodes immediately preceding the successor node. K and L inherit 14 (LS) from M, and it becomes LF for both predecessor activities. Then, we subtract LF times from the duration of activities to find the LS for these predecessors (Figure 7.16). The slack for L is (10-10) or (14-14), which is zero. Therefore, L is also a critical activity. The slack for K is (11-8) or (14-11), which is 3. It means that we can wait for an additional three weeks to start K because we need to wait until week 14.

Figure 7.16: Passing LS times to successors as LF times

4. At a burst point, as is the case when G is followed by two successors, H and I, we pass the lowest LS time of successors (H and I) to the predecessor activity G as its LF time. Therefore, 6 becomes the LF for Activity G (Figure 7.17).

5. When the backward pass is done for all the activities, we can generate all LS and LF times as well as slack times for all of them (Figure 7.18). Thus, we can determine the critical path where the total slack is zero.

The critical path of this project is B – E – G – I – L – M. It is also the longest path. We need to start and finish all these six activities on their scheduled time not to cause any delay in the overall project. Non-critical paths are:

1. A – C – F – J – K – M: 1+2+2+1+3+1=10 weeks
2. A – D – F – J – K – M: 1+4+2+1+3+1=12 weeks
3. B – E – G – H – K – M: 2+1+3+1+3+1=11 weeks

We should always keep in mind that the WBS is not a schedule, but it is the basis for it. The network diagram is a schedule but is used primarily to identify key scheduling information that ultimately goes into user-friendly schedule formats, such as milestone and Gantt charts. The network diagram provides important information to the project team. It provides information about how the tasks are related, where the risk points are in the schedule, how long it will take as currently planned to finish the project, and when each task needs to begin and end.

Schedules must be communicated to project stakeholders. Generally speaking, stakeholders want to know when the work will be completed. Once the completion date is determined, it is important to confirm whether this date can meet the expectations of the stakeholders, in particular the project sponsor, and internal or external clients. Once timeline commitments have been made, stakeholders must be kept up to date on any delays that will cause deviation from the agreed-upon schedule.

Creating a Gantt Chart

A Gantt chart is a type of bar chart, developed by Henry Gantt, that illustrates a project schedule. Gantt charts are easy to read and are commonly used to display scheduled activities. These charts display the start and finish dates of project activities. Gantt charts also show the dependency relationships (i.e., precedence network) between activities.

Gantt charts show all the key stages of a project and their duration as a bar chart, with the time scale across the top. The key stages are placed on the bar chart in sequence, starting in the top left corner and ending in the bottom right corner. A Gantt chart can be drawn quickly and easily and is often the first tool a project manager uses to provide a rough estimate of the time that it will take to complete the key tasks. The detailed Gantt chart is usually constructed after all WBS activities are identified, an activity list is created, activity durations are estimated, and predecessors are determined.

Let's continue with our example in table 7.3. The Gantt Chart for the Scope activities was created by using MS Project (Figure 7.19).

In the Gantt chart in Figure 7.19, red bars show the critical tasks whereas blue bars illustrate the non-critical tasks. Dependencies between all the activities are Finish-to-Start, which is the most common dependency and the default relationship in MS Project.

Project Software

These images use Microsoft Project software, however, most project software will have the same capabilities.

The exercise in Table 7.5 has the same activities, durations, and predecessors as the exercise we used to develop a network diagram. In this exercise, we have added different dependencies (not only F-S), lags (a positive number showing a delay), and leads (a negative number showing an earlier start).

When we start a new project on Microsoft Project, it is useful to check "Project Summary Task" under the "Format" tab. MS Project gives the row number zero to the project summary task. The question mark at the end of the duration shows that the duration is estimated.

Besides, just in the very beginning, it is of high importance to check "Critical Tasks" and "Slack" under the "Format" tab (Figure 7.21). When we type the tasks (activities), the Gantt Chart will start to highlight the critical and non-critical tasks in red and blue colors respectively.

As the durations are in weeks, we should change the settings in the Options under the "File" tab. "Duration is entered in" is changed to "Weeks" (Figure 7.22).

First, we should type each activity on the "Task Name" column and durations on the "Duration" column. Then, we can select the predecessors from the dropdown menu on the "Predecessors" column (Figure 7.23).

When we finish typing all the activity predecessors, Gantt Chart will be completed on the right side of the window (Figure 7.24). As indicated above, red bars show critical tasks (with zero slack) and non-critical tasks (with slacks). MS Project allows the users to change the colors of the bars.

For this exercise, we are not changing the "Task Mode", which is either automatically scheduled or manually scheduled (Figure 7.25). Project summary task is automatically scheduled since it adjusts the duration, and start and finish dates automatically when activity durations and predecessors are typed.

When we double-click a task, the "Task Information" window opens (Figure 7.26). The dependency type is "Finish-to-Start (FS)" as default. Now we can change dependencies as indicated in Table 7.5.

When we are done with predecessor types (dependencies), the predecessors with dependencies different from FS will appear on the "Predecessors" column for the relevant activities (Figure 7.27). These dependencies are shown inside a red circle in Figure 7.27.

After we change the dependencies, it is important to click "Respect Links" under the "Task" tab since the task mode is manually scheduled and the new dependencies may affect the precedence relationships. As can be seen in Figure 7.28, MS Project highlights the boxes in light blue if there is a change.

As can be seen in Figure 7.29, the dependency between A and D is not FS anymore D. It is Start-to-Start (SS). Therefore, the arrow starts from the left side of A's bar on the Gantt Chart and connects to the left side of D's bar. When it is FS, the arrow starts from the right side of the predecessor and connects to the left side of the successor as can be seen in Figure 7.29 between A and C.

In order to see the slacks for each activity, we can add a new column named "Free Slack" (Figure 7.30). The black underline attached to the left of Activity C in the Gantt Chart also shows the slack (Figure 7.29).

Now we can create an activity network diagram by selecting "Network Diagram" on the dropdown menu that appears when we click the Gantt Chart located on the far-left part of the "Task" tab (Figure 7.31).

Figure 7.32 displays the network diagram in a non-collapsed format. We should scroll toward the right to see other activities.

In order to see the whole diagram without details, we should click "Collapse Boxes" and check "Straight Links" under the "Network Diagram Tools – Format" tab (Figure 7.33). The network diagram in MS Project illustrates the links in FS dependency. Therefore, it is convenient to see other dependencies on the Gantt Chart view.

Key Takeaways

• The project schedule management plan is one of the sub-plans of the overall project plan. It provides the guidelines on how to develop a project schedule by defining and sequencing project activities and milestones, and by estimating activity durations.
• The activity definition process is a further breakdown of the work package elements of the WBS which was created while planning the scope.
• After the lowest level activities are defined in the activity list, each activity is reviewed and evaluated to determine the duration. An estimate is an educated guess based on knowledge, experience, and inference. Five types of estimation methods are expert judgment, analogous estimating, parametric estimating, three-point estimates, and bottom-up estimating.
• Showing the activities in rectangles or circles, and their relationships (dependencies) as arrows is called a precedence diagramming method (PDM). This kind of diagram is also called an activity-on-node (AON) diagram.
• Four types of logical relationships (dependencies) are "Finish-to-Start" (FS), "Finish-to-Finish" (FF), "Start-to-Start" (SS), and "Start-to-Finish" (SF). The most common relationship is Finish-to-Start at which we start a successor activity once we finish the predecessor activity.
• The process to create an activity network diagram is composed of two main steps: (1) Forward pass, and (2) backward pass. When these steps are completed, the critical path can be identified.
• A Gantt chart is a type of bar chart that displays the start and finish dates of project activities, and their dependency relationships with one another.