The Project Schedule Part 3: Work Breakdown Structure (WBS)

Planning

A Work Breakdown Structure (aka WBS) takes high level deliverables and breaks them down into lower-level activities suitable for assigning, managing and scheduling work. Creating a WBS is the first step in creating a schedule.

To build a project schedule, you must first define all of the activities that are part of the schedule. If you have created a Project Charter and a Project Plan, you have rich sources of information with which to define the deliverables and the activities needed to produce them.

The Project Charter contains the Project Objectives, which are products, services or results that the project will produce and will survive after the project is over. These are the ultimate deliverables of the project. The Business Objectives contain “Measures of Success” which may require the project to build measurement tools and processes. The Scope section contains high-level activities which can be broken down to smaller pieces for scheduling.

The Project Plan contains the “hows” of the project and most or all of the key project activities were defined there. As the Project Manager, you will need to decide at what level you will define the activities for scheduling purposes. As I mentioned in an earlier post, I am not a fan of Project Schedule’s that contain a large amount of activities as you will wind up putting more effort into schedule maintenance than the benefits you derive.

One common way to define the activities (create a WBS) is to start with the project deliverables and work backwards from there, asking the questions “What inputs are needed for this activity?” and “What activity creates each input?”. For example, for the Requirements Document deliverable, you need final approval. To get final approval, you need to conduct a review meeting. To conduct a review meeting, you need to schedule it. To schedule it, you need a draft document. To get a draft document, you need to write it. To write it, you need to schedule and conduct requirements gathering meetings. And so on until you reach the very first activity which either needs no inputs or the inputs have already been created.

If the deliverable is simple enough you can start from first activity and drill forward. Either method should work. For activities that are not yet well understood or defined, you can define high-level placeholders in the schedule and add the activities needed to obtain the understanding.

Once you have all of the activities, you will work on assigning the resources to the activities and defining the dependencies between activities. I will cover these topics in the upcoming posts.

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The Project Schedule Part 2: Schedule Tools

Planning

For anything but very small projects, you will need a tool to record and track your schedule. The most common tools used for this are Microsoft Project and Excel. They are not the only ones available but they are the ones I will discuss here.

Microsoft Project is a very robust scheduling tool with many features. You enter tasks and sub-tasks, assign resources (you can do this with varying percentages of availability), identify the effort needed for this task (in days or hours), and link the task to dependent tasks. The software automatically creates a schedule from this information.

Often on the first cut at creating a schedule, the project end date is beyond the desired target date. The sequence of tasks that directly connects to this end date is called the “Critical Path”. It is the longest path of dependent tasks in the project. This path of tasks are your top priority to monitor because slippage in any one of these tasks will increase the length of your project.

You must look for opportunities to bring the target date in line with expectations. You can do things like add more resources, bring in more skilled resources, look for opportunities to do tasks in parallel, and/or start some tasks earlier. Be mindful of budget, risk ad quality implications when you use these techniques.

Excel can be used for small and some medium sized projects where you just need a list of key activities and the start and end dates. Unlike MS Project, Excel cannot create the schedule for you. It is used strictly for tracking and communication. It is much more convenient than Project when you don’t need all of the scheduling features.

I advise you not to create a schedule with so many tasks that it eats up your valuable project management time just maintaining the schedule. Create the schedule at a level sufficient enough to track the Critical Path and communicate status to key stakeholders. Keep in mind your Project Plan has all the activity details so there is no need to duplicate all of that information in the schedule.

The Project Schedule Part 1: Overview

Planning

Now that you have a Project Charter, a Project Management Plan and a Project Plan, you can construct a detailed schedule. As mentioned in an earlier post, many refer to the Project Schedule as “The Project Plan”. Since the schedule does not detail how and where tasks are going to be accomplished, it is not “the plan” but is a component of the complete plan. That is why we have a separate document for the Project Plan.

In the upcoming posts I will present the following topics related to constructing a Project Schedule:

  • Part 2: Schedule Tools
  • Part 3: Work Breakdown Structure
  • Part 4: Resource Assignments and Estimates
  • Part 5: Dependencies
  • Part 6: The Critical Path
  • Part 7: Schedule Adjustments (Crashing and Fast-Tracking)