Chapter 21: Estimating Planning Parameters

Overview

The line between project estimation and project planning is wide and blurry. Numerous planning parameters need to be estimated, including how much effort to allocate to construction, testing, requirements, and design; how many testers to have for each developer; how many effort hours you can expect to apply to a specific project in a calendar week or month; how large the risk buffer should be; and many other figures that are needed for planning purposes.

When a project gets to the level of planning discussed in this chapter, the goals of planning tend to be antagonistic toward the goals of estimation. For example, once you estimate the amount of risk buffer you need, the purpose of risk management planning from that point forward will be to minimize the amount of the risk buffer that you actually use, essentially invalidating your estimate.

Estimation of planning parameters is estimation at its least pure: the interplay between fine-grained target setting and fine-grained estimation should be intense and highly iterative. The goal of estimation in this context is to make sure your initial plans are realistic. From that point forward, planning and project control, rather than estimation, should prevail.

In short, planning addresses "how" to conduct a project, and estimation addresses "how much" of a quantity to plan for, which is the focus of this chapter.