Before we get into the details of estimating, let's make sure we are clear on where estimating falls in the schedule development and planning process. If someone stopped you on the street and asked you for an "estimate," what is the minimum information that you would need? You would need to know what the estimate is forwhat work is to be done. And you would need to know who is going to do itwhat type of resources will be involved in performing the work. This is what we show in Figure 7.1. Estimating the work should occur after we have identified the work and after we have thought about what resources are needed for the project.
Figure 7.1. The step of estimating the work in the development of the project schedule.
It sounds so simple, doesn't it? Then why is this so tough? Well, we will cover this in more detail later in this chapter, but these two basic prerequisites are where most estimating woes originate. There is often not a clear or complete understanding of the work to be performed by the person doing the estimate, and the relationship between the work estimate and the resource doing the work is not defined or communicated. In addition, there is the challenge of estimating work that has not been done before in exactly these conditions.
Accurate estimates build the foundation for a realistic schedule and an accurate project budget.
Yet, estimating the work effort is a cornerstone activity for planning the project. From these work estimates, we determine the project costs (see Chapter 9, "Determining the Project Budget"), develop the project schedule (Chapter 8, "Developing the Project Schedule"), and identify key project risks. This relationship is illustrated in Figure 7.2.
Figure 7.2. Shows the foundational role that the WBS and the work estimates play in the overall planning process.
Part i. Project Management Jumpstart
Project Management Overview
The Project Manager
Essential Elements for any Successful Project
Part ii. Project Planning
Defining a Project
Planning a Project
Developing the Work Breakdown Structure
Estimating the Work
Developing the Project Schedule
Determining the Project Budget
Part iii. Project Control
Controlling a Project
Managing Project Changes
Managing Project Deliverables
Managing Project Issues
Managing Project Risks
Managing Project Quality
Part iv. Project Execution
Leading a Project
Managing Project Communications
Keys to Better Project Team Performance
Ending a Project