CMM for Software and CMMI indicate a distinction between achieving an organizational process capability at Maturity Level 4 and performing the prescribed activities to achieve an organizational process capability at Maturity Level 5. For many process improvement professionals, the distinction between Maturity Levels 4 and 5 is a very fine shade of gray indeed. As indicated in Chapter 19, reducing the variation of a process or subprocess by eliminating the special causes of variation and stabilizing the process is only the first step in attempting to achieve the process performance and/or quality. The second and most important step is to find an innovative or incremental solution that will actually result in producing a product that meets the expectations or requirements of the customer. This was called the voice of the customer. The approach to stabilizing the process within its natural bounds was referred to as voice of the process. It was shown that both are needed to have a capable process. The innovations or incremental improvements needed to achieve customer requirements will be explored further in this chapter.

While eliminating the special causes of variation is a necessary step for stabilizing the process and reducing variation, a more interesting next step is to improve the process further by eliminating the common causes of variation. The process area of Causal Analysis and Resolution was developed to support the identification of causes of defects and take action to prevent them from occurring in the future.

This chapter describes the...