Estimating Software-Intensive Systems: Projects, Products, and Processes

Chapter 18Updating Estimates

Inaccurate initial information and inevitable changes mean that you must update estimates during the project. Figure 18-1 shows the same “two loop” diagram shown in Chapter 1, “Introduction.” This chapter describes the actions that occur in the inner feedback loop (loop 1) during the project. To update estimates, you will use the techniques and methods described in Parts 1 and 2 to estimate product size and performance, project effort, cost, and schedule, product quality goals, and process performance goals. This chapter focuses on when to prepare updated estimates, and how to select different methods to exploit the additional information available.

Figure 18-1 Updating estimates during a project

18.1 Reasons ...