2.2.1P Build the Schedule / Process

(2.2.1P.P1)

There are a number of techniques for building a schedule. Perhaps the best option is to utilize a prior schedule from a previous, similar project as your starting point. However, because of the unique nature of projects, that may prove difficult.

A good second choice is to look for a pre-existing schedule template from a project with similar characteristics. For instance, you may be installing a package. Although this is the first time that this particular package has been implemented in your company, you may be able to find a generic template for a package implementation project.

If you do not have a prior historical schedule or a schedule template to use as your starting point, the Work Breakdown Structure (WBS) technique can be used as a starting point. The WBS is a technique for looking at the project at a high level and subsequently breaking the work into smaller and smaller pieces until you can get the full picture of the work that needs to be performed. The entire team can collaborate on this exercise. For the most part, the Work Breakdown Structure technique can always be used as the starting point for creating a schedule from scratch. If you (and others) do not know enough to create a WBS for the project (or at least for the first three months of the project), you probably are not in a position to start the project. In that case, you may want to only define a project for the analysis portion of the project. When the analysis portion is complete, you should have enough information to define the rest of the project. 

Small Projects (2.2.1P.P2)

Usually there is not a formal process used to build a schedule for a small project. The projects are of the size where it is easy to mentally lay out the steps that need to be performed and the order the steps need to be performed. There are probably only one or two people involved, so it is not hard to figure out who does what. Although it may be possible to develop a schedule in your head, the final schedule should be documented. For a small project, you can use a project management package like MS Project or you can use a spreadsheet, or even a piece of paper. The point is to sit down, with other team members if appropriate, and lay out the work to be performed. Having the schedule written down will allow the other team members and your client to understand the work to be performed.

Once you have your initial estimates on effort, cost and duration, you can complete the Service Request form for a small project.

Medium and Large Projects (2.2.1P.P3)

At the smaller end of a medium project, you may have the ability to use the same techniques as for a small project. However, the larger the project, the harder this informal process becomes. In the 2.2.1T Techniques section, there is information on how to build schedules from previous projects or from a pre-built template. These options are usually the best and fastest way to build a schedule for your project. For the purpose of this section however, the assumption is that you have to build the schedule from scratch. The best way to do this is to start with a Work Breakdown Structure (WBS) and define the schedule from there. The general process is as follows:

 

Role

Building a Schedule from Scratch

1

Project Manager

 Create Schedule Management Plan

This document defines and communicates how the schedule will be maintained throughout the project. It is part of the Project Management Plan. See 2.1.3.4P Create Schedule Management Plan for more details.

Gather Pre-existing Baseline Documents (2.2.1P.P4)

2

Project Manager

Review the Project Charter draft to ensure you understand the deliverables, the overall timeframe, risks and assumptions, etc. The Project Charter may not be complete, but it needs to be in decent first draft form so that the draft schedule can be built. The Project Charter and any other relevant documents should be reviewed before you start to build the WBS.

Activity Definition / Create Work Breakdown Structure (WBS) (2.2.1P.P5)

3

Project Manager

Create a Work Breakdown Structure

The purpose of the Work Breakdown Structure is to capture all the detailed elements of work required to complete the project. Sequencing is not important at this time. This process of breaking larger work components into smaller work components is called “decomposition”. When the Work Breakdown Structure is complete you have an inverted (upside-down) tree structure of activities. The high-level project itself is referred to as level 0 and the first high-level breakdown of work is called level 1.

For additional tips and techniques for building a Work Breakdown Structure, see 2.2.1.5P Basics of the Work Breakdown Structure.

4

Project Manager

Estimate the work effort for all detailed activities

you have previously done a high-level estimate of effort to determine if the work for each activity is greater than the estimating threshold. You now need to review all the detailed activities and estimate the actual effort hours (the detailed activities are the ones at the lowest level that are not broken down further). You can use estimating techniques found in 2.2.1.1P Estimating Effort and Duration and 2.2.1.2T Estimating Techniques for Schedule and Budget.

Sequence Activities (2.2.1P.P6)

5

Project Manager

Sequence the detailed work components

The first step in converting the Work Breakdown Structure into a network diagram is to look at all the detail activities (not the summary activities) and sequence them in chronological order. Remember to include all the activities that are not broken down further, regardless of what level they are at in the WBS. In the sequencing process, you determine the work that gets done first, second, third, etc. You also determine the work that can be done in parallel with other activities. This step is the reason why it does not matter how you structure the initial WBS. As long as you discover all of the work in the WBS, the sequencing of the activities is done now.

When you have a rough sequence established, go through the work again. At this time look for all the relationships and dependencies between the activities. You should note whether one activity cannot start until another activity is finished. In many cases, two or more activities may need to be completed before another one can start.  More information on establishing the activity sequence is available at 2.2.1.3P Precedence Relationships.

6

Project Manager

Determine the critical path of the project

Once you have completed sequencing the activities, your schedule will have many paths of dependent activities that go from the beginning to the end of the project. There is one path that is more important than any other path – the critical path. This is the one path that is driving the project end date. See 2.2.1.7P Critical Path for more information on this very important concept.

7

Project Manager

Look for date constraints

Next you should enter any date constraints. Date constraints are events that are outside of the control of the project team and must be managed around. They are not necessarily problems or risks, but they need to be taken into account for the purposes of your schedule. Many constraints have date implications, but not all do. For instance, a deliverable may need to be completed before the Board of Directors meeting on a certain date; or, you may need to place an order with a vendor by a certain date.

Estimate Activity Resources (2.2.1P.P7)

8

Project Manager

Assign Resources

So far you have built the plan without specifying any resources. In this step, you assign resources to the work activities. If you have specific resources allocated to your project, you can assign them directly to the appropriate activities. If you do not have all your resources assigned, this resource assignment will need to be by a generic type of resource. For instance, if you have three 'programmers' assigned, you may need to assign them to the schedule as 'programmer1', 'programmer2' and 'programmer3'.

Estimate Activity Durations (2.2.1P.P8)

9

Project Manager

Create the initial project schedule

If you are using a tool to do the initial scheduling of the project, go ahead and create an initial schedule now. Based on the effort hours, resources and constraints, the tool will calculate the overall timeline of the project from beginning to end.

10

Project Manager

“Level” the resources

In the prior steps you assigned resources based strictly on which resources could do the work. What you may find is that a resource may be allocated for too many hours one week and not enough hours the next week. In this step you check to see if resources are over-allocated or under-allocated. Smoothing out this workload is called resource leveling. Techniques for leveling resources include:

  • Scheduling activities sequentially, even though they could be done in parallel if not for resources constraints. For instance, you may have two activities, each estimated at 40 hours, that can be worked on at the same time. However, the same resource is needed to work on both. In this case, one activity needs to be scheduled first and the other activity needs to be done afterward.

  • Move work from one person who is over-allocated to another person with similar skills that is under-allocated in the same timeframe.

  • Look for slack elsewhere in the schedule and push some work there. For instance, an activity may have 5 days duration, but can be completed within a 30-day window. A resource may need to work on many other activities first, but have some available time toward the end of the 30 days. In this case, the more flexible activity can be scheduled later, after other less flexible activities have completed first.

  • Change the resource mix. If two (or more) people are assigned to an activity, see if one person can be freed up to work on another activity that is resource- constrained, even if the first activity now takes longer to complete. Likewise, see if additional resources that are under-allocated can be added to an activity to accelerate its completion and then allow another activity to be started earlier. 

 

After the initial schedule is run, Joe is over-allocated on days 8 and 9. After resource leveling, some of the work is moved to day 10, and the rest of the work is moved to day 11. The activity now extends into an extra day of duration, but does not over-allocate Joe.

11

Project Manager

Adjust plan

After you have estimated the effort for each activity and assigned resources, you can again schedule the project and see how long it will take (duration). At this point you have your first real draft of a schedule.

Develop Schedule (2.2.1P.P9)

12

Project Manager

Review the schedule to see if it makes sense

You need to feel comfortable to defend your estimates to your manager and sponsor. If you feel that the schedule doesn’t reflect what you need, make changes and reschedule. For instance, your schedule may show duration of ten months, but you may only have eight months to get it done. At this point, you can look at alternatives such as adding resources, working some overtime, removing some of the work activities, etc.

You should feel comfortable that this estimate of project duration is within 15% before you start the project. 

The bottom line is that when you provide the estimate for the schedule, others may question your numbers. If you don’t feel comfortable enough to back them up, you have more work to do, In other words if you cannot defend your numbers, you should spend more time trying to create an estimate that you feel confident in.

13

Project Manager

Establish milestones and gate reviews

Determine when key deliverables will be completed and assign milestones to those events. A milestone is an activity with zero duration that is used to help manage the work at a high level. If you run a report showing the project milestones, you should be able to quickly tell whether you are on schedule, ahead of schedule or behind schedule.

You can plan project reviews at the major milestones. This technique is called a “phase gate review”. You can see more details at 2.2.1.8P Establish Phase Gate Reviews. The actual purpose and format of the Phase Gate Review is described at 4.1.1.3.2P Milestone / Phase Gate Reviews.

14

Project Manager

Save a current copy of the schedule as a baseline

Once the schedule is completed and the project is approved, save a current copy of the schedule as a baseline version. Later on when the schedule is managed, the updated schedule can be compared against this original baseline version to determine variances.