TABLE OF CONTENTS This chapter is designed to help the reader understand the basic tenets of Maturity Level 4 in the staged representation of the CMMI. However, because this chapter consists of summaries of the process areas, anyone wishing to get a better idea of the model, no matter which representation is to be used, can benefit from this chapter. Once again, we are not attempting to teach the CMMI. We simply offer a condensed version of the various areas and key points to consider.
Level 4 is all about numbers. The projects are managed "by the numbers." Organizatonal decisions are made "by the numbers." Processes, services, product quality are all measured "by the numbers." At Level 4, the organization has achieved all of the goals of Levels 2 and 3. Processes, although qualitatively stable and predictable at Level 3, can be proved to be quantitatively stable and predictable at Level 4. The major difference between Level 4 and the next level, Level 5, is that Level 4 analyzes the data collected, determines special causes of variation from the norm, and supports quantitative management and control. You do this to make your processes predictable. Level 5 addresses common causes of variation. So, for Level 4, an organization needs data that are stable and consistent. The major preoccupation of assessors when reviewing Level 4 is, "Did this organization mix apples and oranges? Are the data really accurate? Did this organization collect the right...
