Breaking Down the Project Activities

Overview

This chapter continues our journey deeper into the Planning recesses of project management. Along the way, we'll define tasks and activities, construct a work breakdown structure (WBS), and discuss how to estimate activity durations.

Creating the overall project plan involves many preliminary and incremental steps. This chapter will get us a little closer to the creation of a project schedule, which is one of the most important Planning documents you'll create. Paying close attention to the creation of the work breakdown structure, defining milestones, and activity sequencing will make the job of creating the project schedule much easier.

At the end of this chapter we'll take a look at some diagramming methods for project activities. As they say, a picture is worth a thousand words, and network diagrams help the stakeholders and project team visualize the workflow of the project.

In this chapter, you will learn:

• Defining tasks and activities
• Constructing the work breakdown structure
• Setting milestones
• Constructing the Responsibility Assignment Matrix
• Making activity estimates
• Constructing network diagrams

Defining Tasks and Activities

Your first job in this section involves deciding whether you like the term tasks or activities to describe the work of the project. Most project managers use these terms interchangeably. This isn't the only controversy you'll run across in project management circles, but it is one of the lighter ones. For the purposes of this book, I'm going to stick with the term task most of the time, but if you see activity in some places, know that I'm talking about the same thing. We will talk later about activity estimates and network diagramming, which both use the term activity, but keep in mind when we get there that activity and task mean the same thing. Now that we have that out of the way, let's look at what tasks are and the purpose of the task definition process.

Tasks are a single piece of work, or units of related work, that must be completed in order to satisfy a project deliverable or the requirement of a deliverable. When you've completed all the tasks of the project, the product or service of the project is complete. And there you have it—define all your tasks, complete them, and your project is complete. Hold on, it's not quite that simple; there's more.

Tasks are derived from the project deliverables and from the requirements of the deliverables. You defined those in the scope statement. You'll see as we progress that almost everything we do in the Planning process builds on itself, so it's important to take each process seriously and do the best job you can because you're going to be relying on that information later.

Managing the Work

The purpose of task definition is to allow you to break down the work of the project into manageable components so that you can easily determine time, resource, and cost estimates. Each task should be broken down to the point where these estimates are easily derived. Breaking down the deliverables into tasks makes the project manager's job easier because the work is subdivided into small units that are easily assigned to one team member or a group of team members. You can communicate the details of the work to the right team members, manage and track project progress, and provide a way to logically group similar tasks together.

Note 

An easy way to differentiate between deliverables and tasks is to describe deliverables as nouns (people, places, or things) and use verbs, or action words, for your tasks—words like define, prepare, program, design, build, research.

Let's look at an example. You've been assigned as the project manager for your company's upcoming annual conference. Customers from all over the world fly to your city to attend this conference and learn about your company's products, take some training classes, and meet with vendors. One of the deliverables of this project includes connecting and setting up 200 PCs for use at the training seminars held during and after the conference. One of the tasks associated with this deliverable might be loading software on each PC. Another task might be to run two power strips for each table in the ballrooms of the hotel where the training is being held.

At this point, you don't need to worry about in which order the tasks appear; just start a list of tasks for your project and give yourself room in between each major heading to come back and add to them. You'll find as you start breaking down tasks that you'll think of new tasks for some of the deliverables you've already broken down, so if you leave yourself some space, you can add these tasks as you think of them.

I'd recommend using a simple format that lists the deliverables as the main heading with task breakdowns and comments under the deliverables. If your project is good sized, you might list each deliverable on a separate page (or pages). A small project may have only a few pages of combined deliverables with their tasks. An example task list for some of the tasks needed for the "Set up PCs" deliverable is shown in Table 5.1. If you're going to use this as a template, I'd add the General Information section to the very top of this form like we had on the scope statement and charter documents to help identify basic information about the project (project name, project number, date, etc.).

Table 5.1: Task List

Deliverable	Tasks	Comments
Set up 200 PCs for training seminars the evening before the conference begins in the designated ballrooms.	Sign lease agreement for PCs.	Coordinate with procurement department.
	Arrange delivery of PCs.	Part of lease agreement.
	Run electric extension cords and power strips.	Coordinate with hotel staff.
	Load software.	Coordinate with IT department.

Task Sequencing

After you define the tasks, you'll want to sequence them in a logical order. This will help you when you're ready to create the project schedule later on. For example, you can't load software onto the PCs until they've been delivered and they have a source of electricity, so it makes sense to list the "Load software" task last in this list. When you're working on small projects, you can easily combine the task definition with the task sequencing process. As you list the tasks, group them into a logical order at the same time. Larger projects require a two-step process. First identify the tasks; then sequence them.

Task sequencing also provides a way for you to keep similar types of work together. In our example project, the IT department is in charge of hooking up the PCs and loading the software. They also have the responsibility for setting up the PC connections from the speaker's podium to the overhead projection system. A logical place to include these tasks would be in our task list shown earlier in Table 5.1. In other words, we've grouped tasks that are similar in nature in the same place.

Task identification and sequencing allows the project manager to define estimates and costs and to determine the skills needed for the work of the project. For instance, the task called "Load software" tells us what type of skills are needed to complete this task. Obviously, we need folks who have some understanding of how PCs work and how to troubleshoot problems if the software doesn't load correctly. This means that we're going to have to work with the functional manager of the IT group to assign some resources to these tasks or contract with a vendor to perform these tasks for us.

Your project budget, the project schedule, and resource assignments are determined primarily from the task identification phase and sequencing exercises. As you can see, these are important steps in the project Planning phase, so you want to take the time here to do a thorough job. But don't feel that you're out there all on your own. Hold a team meeting or two and do some brainstorming to come up with all the tasks necessary to complete the deliverables. Then, after you've compiled your final list, review the list with the team before moving on to the network diagramming or project schedule phase to be sure you haven't missed anything.

Determining Milestones

If you're over the age of 15, you've experienced some milestones in your life: Reaching age 16 (driving!), then 18 (graduation from high school), then 21, and, well, you get the idea. Milestones in projects work the same way. Milestones are markers along the way that let you know that a significant accomplishment has been reached. Milestones are not tasks but they can consist of a grouping of tasks. You don't perform actions to complete a milestone; in other words, they aren't work. Instead, they signify that a grouping of work has been completed or a significant accomplishment has been reached.

Milestones might be based on deliverables, or a grouping of deliverables, or a grouping of tasks. For example, one milestone for our conference project might be, "Ballrooms prepped and PCs set up for training."

Some project managers like to use milestone charts as one way to report on project progress. A milestone chart should include a listing of the milestones with their expected completion dates and their actual completion dates. Table 5.2 shows a sample portion of a milestone chart for the annual conference project.

Table 5.2: Milestone Chart

Milestone	Expected Completion Date	Actual Completion Date
Vendor registration complete	05/15/03	05/15/03
Website updated with conference info	07/01/03	07/01/03
Brochures mailed to prospective attendees	08/01/03	08/01/03
Training classes designed and approved	09/15/03
Ballrooms prepped and PCs set up for training	11/14/03

Milestones are a way to help monitor the progress of the project. They are a great tool to use for reporting to executive management because they show at a glance where the project stands and what remains to be completed. Milestone charts work particularly well for smaller projects.

Another way to display milestone charts is in a Gantt chart format (we'll discuss Gantt charts in Chapter 8, "Developing the Project Plan"). You can display the start date of the milestone and its duration. Milestones should be listed in the order in which they'll be accomplished in the project.

Constructing the Work Breakdown Structure

A work breakdown structure (WBS) is a tool used to graphically display the deliverables of the project in a hierarchical fashion. It organizes the work of the project into logical groupings similar to a milestone chart but displays the information in a tree form or an outline form.

work breakdown structure (WBS)

A deliverables-oriented hierarchy that defines all the work of the project. Each succeeding level has more detail than the level above it.

Note 

Only the work of the project is included in the WBS. If the work is not included in the WBS, it's not part of the project.

Only the work of the project is included in the WBS. This may seem obvious, but if the work isn't shown in the WBS, it's outside the scope of the project and should be noted as such. (Back in Chapter 4 we included a section in the scope statement to note deliverables that are out of scope for the project.) This is an important distinction to make. Many projects suffer from scope creep, whereby the project seems to grow and grow the further you get into it. You no sooner have a list of deliverables and begin working on completing them when more deliverables are "discovered" and the deliverables you previously defined are modified or altered. Thus the scope of the project grows to a point where the original project estimates are no longer valid because the new requirements have added additional tasks to the project.

scope creep

A phenomenon where the scope of the project changes over time because of lack of agreement on the original scope statement, not sticking to the original scope statement, or not having a scope statement.

If you've done a good job writing your scope statement and then depict that work accurately in the WBS, you'll go a long way toward eliminating scope creep on the project. This also implies that you've kept the project team and stakeholders focused on the original scope statement and have not allowed changes that would alter the scope. Legitimate changes that must be made in order to ensure project success are another matter, but we'll take that up in Chapter 11, "Controlling the Project Outcomes."

Organizing the WBS Levels

A WBS is similar to a company organization chart or a family tree. It can also be shown in outline form, which we'll get to shortly. It starts out with the big picture, and each successive level gets more and more detailed. Like an org chart, it's a hierarchically oriented view that shows which tasks "report" to which dependencies. There is no set number of levels in a WBS, but I'd recommend not going more than five or six levels deep because the WBS will get bogged down in too much detail. If you're working on a large project you will have sub-project managers working with you who will be responsible for developing their own WBS from the project level WBS. We'll cover this in more detail at the end of this section.

Whether you choose the tree form or the outline form, the levels and organization of the WBS remain the same. The highest level of the WBS, level one, is the project level. The next level holds the deliverables or major milestones of the project. The succeeding levels are further breakdowns of the deliverables that may include tasks or groupings of tasks. Does this sound familiar? The deliverables are defined in the scope statement, and you defined the tasks in the task identification process. Now it's a matter of plugging them into the WBS. Keep in mind that for small projects you could skip the task identification process and perform it at the same time you're defining the WBS. Until you're experienced at this, though, you should break down the tasks first and then plug them into the WBS.

Remember when defining your WBS levels that deliverables are typically described as nouns or as past-tense events such as "PCs set up," "Brochures mailed," etc. Tasks, which are developed from the deliverables, are usually described as action words: create, develop, establish, and so on.

Let's look at some examples. The next graphic shows the level-one and level-two details for our conference project. Keep in mind that the level-two deliverables in this figure are only a sample. Your project would have many more deliverables than this.

Level one shows the project name. This is always the first level in any WBS. Level two for this WBS shows some of the deliverables or milestones for this project.

Now let's take a look at the next two levels:

Level three in this WBS shows a grouping of tasks, sometimes called summary tasks. For example, "Obtain PCs" is a summary task under the "PCs set up" deliverable found at level two. The "Obtain PCs" summary task at level three has tasks under it that must be completed in order to consider the "Obtain PCs" summary task complete. In order to complete the deliverable called "PCs set up," the two level-three summary tasks shown on the WBS, "Obtain PCs" and "Set up PCs," must have all of their tasks completed. The same is true for the other deliverables.

The idea is to start the WBS with the project and then continue to break down the deliverables into smaller, more manageable units in each subsequent level. These levels could include milestones, a grouping of tasks, or individual tasks. The idea is to keep adding levels to the WBS until you've broken the work out to the point where responsibility for each unit of work can be assigned to a specific person or to a team. This is also the level that allows you to easily determine estimates and the skills needed to complete these tasks.

Work Packages

A work package is the lowest level of a WBS. This is the level where assignments, estimates, and resources are easily determined. It doesn't matter whether the WBS has three levels or five levels; the lowest level in either case is considered the work package level.

work package

The lowest level in a WBS. Resource assignments and time and cost estimates are established at this level.

In the WBS shown earlier, level four is the work package level. In that example, the individual tasks like 10.1.1 Sign lease agreement and 10.1.2 Arrange delivery are the work packages and are assigned to individuals or teams to complete. If we broke off the WBS at level three—in other words, if we didn't include level-four tasks—then level three would be the work package level.

Note 

The lowest level in any WBS is called a work package. Work packages can be sub-projects, milestones, deliverables, or tasks, depending on how the WBS is structured.

Work packages may include individual tasks, milestones, or subprojects within the project. If you're working on a very large project, the project should be broken down into smaller subprojects rather than individual deliverables. Level one still remains the overall project, level two becomes subprojects within the project, and level three may also be subprojects within the subprojects, or this level might start the breakout of deliverables. In this case, level three is the work package level. Here is an example WBS with projects and subprojects.

In a structure like this, subproject managers may be assigned to the level-two subprojects. All subproject managers report to a single project manager who has responsibility for the overall project. Level-two subproject managers (also called assistant project managers) assign the level-three subprojects to teams or individual project assistants. At this point, the project assistants create their own WBS for the level-three subproject they've been assigned. For large projects, you can see that this could get rather complicated. However, the effort is well worth it in the end since you have a logical, graphical depiction of the project breakdowns in one place.

Once the WBS has been reviewed and approved by the project manager and project sponsor, it's a good idea to tape up a copy of it in the project team meeting room. And don't forget, a copy of the WBS should be filed in your project note-book for future reference.

Identification Codes

You may have noticed numbers next to each of the WBS elements. These identifiers, or WBS codes, allow you to uniquely identify each element of the WBS. They're used to track the cost of the work, or the cost of each element in the WBS. They also serve as reference numbers to other planning information. As you begin assigning tasks and defining resource needs and such, you'll want to document some of this information (the act of documenting will become contagious over time), and the codes provide you a handy way to tie the information back to the WBS. For example, you might want to note that WBS item 10.2 was assigned to the IT department. Maybe there are several costs involved with this summary task that you need to break out. That information can be recorded in the WBS reference document or WBS dictionary. The dictionary is created as a simple Word document or spreadsheet document that lists each WBS reference number down the left side with comments regarding that WBS element to the right. This document should be filed in the same section of your project notebook as the WBS.

Your budget officer will need these numbers as well to track the cost of the project. Depending on the WBS you've constructed, level-two and level-one elements are simply a roll-up of the costs from all the levels beneath them. These codes come in handy when using the outline view for the WBS. We'll look at that next.

Outline View

There's one more version of the WBS you can use if you don't like the tree form. The outline form works well for small projects or projects that have multiple levels with lots of tasks.

This list shows a snapshot of the same information we saw in the first WBS graphic but in outline form. The WBS identifiers are especially important in an outline form because they help you easily determine which task goes with which deliverable.

10.0	PCs set up
	10.1	Obtain PCs
		10.1.1	Sign lease agreement
		10.1.2	Arrange delivery
	10.2	Set up PCs
		10.2.1	Install power strips
		10.2.2	Load software
20.0	Brochures mailed
	20.1	Prepare brochures
		20.1.1	Design brochures
		20.1.2	Print brochures

I think you can see that if you've done a fabulous job of documenting the deliverables in the scope statement and identifying your tasks, the WBS almost can't miss. If the scope statement is inadequate or the deliverables and task identification were poorly developed, the WBS will also be poorly developed. This will cost you in the end in the form of rework. Rework means that you have to go back and redo things you've already done or add tasks that you missed. And remember way back from Chapter 1, "Building the Foundation," that time equals money, so if you're involved in rework or you're adding new tasks to the WBS after it's been approved, project costs are going to escalate. Take the time to construct your WBS correctly and review it several times with the project team.

Tip 

Don't be alarmed if you uncover new deliverables as a result of creating the WBS. Updates to the scope statement may occur two or three times throughout the Planning process.

Don't forget that as you create the WBS, changes to the scope statement may result. That's to be expected at this point in the project, so when the WBS is completed, go back through your scope statement to make sure all the deliverables are reflected there. If not, follow the procedures outlined in the scope management plan and update the scope statement to reflect the additions. (Don't forget to get sign-off on the changes.)

Constructing the Responsibility Assignment Matrix

We've seen a couple of examples of roles and responsibilities charts in the preceding chapters. The Responsibility Assignment Matrix (RAM) is the same idea. After you've constructed your WBS, you're ready to determine the types of skills and resources needed for the project. The RAM will help you do that.

Responsibility Assignment Matrix (RAM)

A chart that ties roles and responsibilities with the WBS elements.

A RAM is usually depicted as a chart, with the types of resources needed listed in each row and the WBS elements as the columns. The intersection of a row and column contains an indicator that shows what level of activity is needed by the resource. This could consist of a simple word like Approve or Review, or it could contain a code that ties to a legend if you need to be more specific than a one-or two-word description.

Table 5.3 shows an example RAM for the "PCs set up" summary task.

Table 5.3: Example RAM

Resource	Lease Agreement	Install Power Strips	Load Software
Procurement Dept.	Create	N/A	N/A
Hotel staff	N/A	Install	N/A
IT Dept.	N/A	Review	Install

You could put actual names in the Resource column if they're known at this time. If you don't yet know the names of the folks responsible for these tasks, listing the department name as we did in Table 5.3 will work just as well. Later in the planning process you will want to associate someone's name with each of these tasks so that responsibility for the completion of this task is assigned to a person. We'll discuss assigning activities in Chapter 6, "Planning and Acquiring Resources."

RAMs can be developed for any level in the WBS. When you're working with subprojects within a major project, you might use RAMs for the level-three elements in the overall WBS and additional RAMs for the elements in the individual work breakdown structures constructed for the subprojects.

Estimating Activity Durations

Estimating activity durations is the next activity we'll undertake after constructing the WBS and RAM. The reasons why you constructed the WBS and the RAM first are so that you know which tasks you need estimates for and you know which resources you can ask to help you determine those estimates.

Activity duration estimates determine the number of work periods needed to complete the tasks defined in the WBS. Work periods are expressed in hours, days, weeks, or months. Hours and days are the most common work periods used, but you may need to use weeks or months if your project is large or is expected to take a long time to complete.

There are several techniques for determining activity duration estimates. A few of them are interchangeable with the budget estimating techniques we'll discuss in Chapter 9, "Budgeting 101." We'll look at two examples here that are used most often for activity durations, but keep in mind that there are other techniques, described in the budgeting chapter, that you could use as well.

Expert Judgment

Expert judgment is just what it sounds like. When you've determined the type of resource needed to perform the task, you can ask staff members who are experienced at these types of activities to give you an estimate for those tasks. Because of their experience with similar activities in the past, they'll be able to give you a fairly decent estimate. However, this is not a scientific method, and the person giving you the estimate may historically over-or underestimate durations based on their biases. To help even out these biases, you could ask more than one expert for an estimate and then combine their results. If possible, combine their expert judgment with historical information from past projects (remember those project notebooks filed away with all that juicy project information waiting for you to use as a reference?) to determine an estimate.

expert judgment

Using individuals or groups of people who have training, specialized knowledge, or skills to help assess information and determine estimates.

Quantitatively Based Durations

This type of estimate works with known quantities and calculates estimates based on the quantity of elements needed to complete the task. For example, you know that it takes six minutes to seal, stamp, and print the address on 5,000 brochures. If you're going to mail 50,000 brochures, you calculate the duration for this task by multiplying six minutes times ten to come up with a total duration of sixty minutes to seal, stamp, and print 50,000 brochures.

These duration estimates are initial estimates right now. You will have a chance to refine these, and you should refine these again when you create the project schedule. At that time, you'll have more information about the tasks, and your project team will be in place, so you'll have what you need to fine-tune these estimates.

Establishing Dependencies

When tasks are dependent on one another, it means that one task cannot start or finish until the previous task has finished or started. In order to determine dependencies you have to put the tasks in logical order. We talked about that earlier in this chapter in the section called "Task Sequencing." Now you'll determine whether the tasks are stand-alone tasks or they are tasks with dependencies.

Tasks with dependencies must be sequenced in the correct order or you'll end up doing a lot of rework. As an example, the "Load software" task is dependent on the "Install power strips" task because if you don't have power, you can't power up the PC and load the software. This is an example of a mandatory dependency because of the nature of the work. One action can be performed only after another action has taken place.

Not all tasks have dependencies; some tasks may be independent, or standalone. The "Load software" and "Install power strips" example is what's called a Finish to Start dependency relationship. That is, the "Install power strips" task must finish before the "Load software" task can start.

There are four types of dependency relationships. Let's take a quick look at each.

Finish to Start The independent task (the "Install power strips" task from the earlier example) must finish before the dependent task (the "Load software" task) can start. This type of relationship is the most frequently used dependency. Most of the tasks in our annual conference project that have dependencies have Finish to Start dependencies.

Finish to Finish The independent task must finish before the dependent task finishes. There isn't an example of this type of relationship in our annual conference project. But an example from the kitchen will help to explain this relationship. When you're making a roast beef with gravy (assuming you're making gravy from the pan drippings), the roast beef must finish cooking before the gravy can finish. You can start the gravy anytime by mixing the flour and water together, but you can't add it to the pan drippings until the beef has finished cooking. Therefore, these tasks have a finish to finish relationship.

Start to Start The independent task must start before the dependent task starts. For example, when preparing the training materials for our annual conference, we might want to review materials as they are written rather than waiting for all the materials to be written and then reviewing them all in one step. Therefore, the "write content" task and "review content" task have a start to start relationship. You cannot start the "review content" task until the "write content" task has started.

Start to Finish The independent task must start before the dependent task can finish. This dependency is seldom used.

You need to understand the dependency relationship between the tasks in order to diagram them, as we'll see in the next section.

Constructing a Network Diagram

A network diagram allows you to show the tasks of the project in the order they'll be performed—in other words, in sequential order. A network diagram is a graphical view of the project starting with initiation as the left-most element followed by all the project tasks or deliverables in the order they should be worked. Some tasks have dependencies like those we discussed in the last section, and some are stand-alone. The stand-alone tasks are often worked at the same time as other stand-alone tasks unless, of course, you're the only resource working on the project. Then you have no choice but to work one task after the other in sequential order. Most projects have more than one resource, though, and that means that those stand-alone tasks can be worked at the same time by different resources.

The network diagram allows you to visually construct and link the tasks the way they should be worked. It's also a great graphic to hang in the project team meeting room to show your progress.

You may be thinking that we did all this with the WBS. Not really. The WBS is in a hierarchical layout, not a sequential layout. For example, if you refer back to our WBS example, you'll see that "Prepare content" and "Prepare media" are two different deliverables displayed in a hierarchy. However, based on our previous discussion of dependencies, you can see that the "Print materials" task cannot (or should not) be done before the "Review content" task is completed. Since these tasks are listed under separate deliverables, there isn't a good way on the WBS to show their dependencies. While all the tasks under each of these deliverables are ordered logically, they aren't shown in dependency order. A network diagram allows us to show the flow, or sequence of tasks.

Note 

A WBS does a much better job of displaying milestones and deliverables than a network diagram does. A network diagram is better at showing the sequence of tasks, so both of these tools have their place in the project planning process.

A network diagram, like the WBS, can consist of subprojects, deliverables, mile-stones, or tasks. If you're working a large project, the network diagram will likely display the sequential order of all the subprojects. (Each subproject manager is then responsible for developing a network diagram for their individual subprojects.) Small projects will likely show the tasks in sequential order. As you've probably guessed, there is more than one way to construct a network diagram, so we'll look at an overall description first, followed by three different methods of drawing the diagrams.

Precedence Diagramming

Precedence diagramming is simply plotting the tasks in a diagram format in the right order according to their dependencies. This is also known as activity on node, which we'll cover in the next section. Precedence occurs when one task cannot be started until a previous task finishes, such as the "Load software" task we talked about earlier. The "Install power strips" task has precedence over this task because it must be finished before the next task can start.

precedence diagramming

A diagramming method that links project activities according to their dependency, using nodes to depict project activities and arrows to show dependencies.

Precedence diagramming is the method of placing tasks in the correct sequential order, taking their dependencies into account. It also takes into account tasks that can be worked at the same time and tasks with multiple dependencies. Most project management software programs use precedence diagrams. Here is a sample precedence diagram for the tasks in our annual conference project.

The numbers in the diagram are a way to identify the tasks. The numbers are not in sequential order; they're just a way to identify each task. Here, I've added two new tasks: number 10, "Test," and number 11, "Sign-off." For the sake of this example, we'll assume that the "Review" task, number 7, means a grammatical review of the text, while the "Test" task means that testers must work through each exercise in the manual to make certain they can understand them. The "Print media" task now has two tasks that must be completed before it can begin. Task number 7, "Review," and task number 11, "Sign-off," must both be completed before "Print media" can begin. Remember that "Sign-off" also has a dependency. The "Test" task must be completed before "Sign-off" can be obtained.

You can see how a network diagram is a terrific tool to visualize the progress of the project. You can view the project in one graph (maybe two or three or more if the project is complex), determine how the work of the project must be performed, and see what dependencies exist between the tasks. As you progress, you can indicate on the network diagram itself which tasks have been completed by checking them off or coloring them, etc.

In Chapter 8, "Developing the Project Plan," we'll discuss establishing starting and ending dates for each task. These can be added to the top corners of the box for a more complete picture.

Activity on Node

Activity on node (AON) is a precedence diagramming method that uses circles, called nodes, to depict the tasks, and arrows to show the dependencies between the tasks. AON diagrams can be constructed with boxes as nodes like we saw in the previous section. In the example shown next, a sample portion of the activities, or tasks from our annual conference project, are placed on the nodes, and the arrows show the dependency between the tasks.

This example shows the "Print media" task dependent on the completion of the "Sign-off" and "Review" tasks. You could add more detail to this diagram by showing the duration estimates on the arrows for a clearer picture of how long each task should take. We'll discuss this technique further in Chapter 8.

Arrow Diagramming Method Activity on Arrow

Activity on arrow (AOA) is the opposite of the AON diagram. It also uses nodes and arrows like the AON, but in this case, the arrows depict the activities or tasks and the nodes indicate milestones or deliverables or simply events between the activities. Here is an example of an AOA.

Precedence diagrams are the easiest type to construct and the most often used. If you can draw boxes and straight lines, you can assemble a precedence diagram. I encourage you to draw a network diagram for your project and display it, along with the WBS, in the project team meeting room. And as you've heard consistently about other project documentation, put a copy of this diagram in your project notebook.

Terms to Know

• expert judgment
• precedence diagramming
• Responsibility Assignment Matrix (RAM)
• scope creep
• work breakdown structure (WBS)
• work package

Review Questions

1.	What is the purpose of task definition? ____________________________________________________________
2.	Name some of the purposes of task sequencing. ____________________________________________________________
3.	What are milestones and what significance do they have to the project? ____________________________________________________________
4.	Describe a work breakdown structure. ____________________________________________________________
5.	What is a work package? ____________________________________________________________
6.	Why are codes used to identify elements in the WBS? ____________________________________________________________
7.	Define a RAM and explain how it's used. ____________________________________________________________
8.	Name two methods of determining activity duration estimates. ____________________________________________________________
9.	Describe the four types of dependency relationships and indicate which one is used most often. ____________________________________________________________
10.	Name three ways to display network diagrams and briefly describe each. ____________________________________________________________

Answers

1.	The purpose of task definition is to break down the work of the project into manageable components in order to establish time, resource, and cost estimates.
2.	Task sequencing puts the tasks in a logical order. This will help you build the project schedule. It's also a means of grouping similar types of work together.
3.	Milestones signify important accomplishments that have been achieved on the project. They are not work in themselves but consist of a grouping of tasks that when completed are a significant portion of the project.
4.	A WBS is a tool used to graphically display the deliverables of the project in a hierarchical fashion. They can be displayed in tree form, much like an organizational chart, or in outline form.
5.	A work package is the lowest level of a WBS. This is the level where resource assignments, estimates, and costs are assigned.
6.	Codes are to track the cost of each element in the WBS, generally at the work package level. They also serve as a reference number to identify the WBS element and tie it to explanatory information.
7.	A RAM is a Responsibility Assignment Matrix. It's used to show what types of resources are needed for each element of the WBS. These are constructed in chart form, and the intersection of a row and a column indicates the level of activity needed by the resource for that WBS task.
8.	Two methods used to determine activity duration estimates are expert judgment and quantitatively based durations.
9.	The four types of dependency relationships are Finish to Start, Finish to Finish, Start to Start, and Start to Finish. The most often used dependency is Finish to Start, which says that the independent task must finish before the dependent task can start.
10.	The three ways to display network diagrams are precedence diagramming, also known as AON, and AOA. Precedence diagramming is a method of placing tasks in the correct sequential order, taking their dependencies into account. There are two ways to display precedence diagrams. One method displays activities in boxes or nodes, with arrows showing the dependencies between the nodes. The activity on node method displays activities in circles or nodes, with arrows showing the dependencies between the nodes. Activity on arrow displays the activities on the arrows, with milestones or events represented on the nodes.