Figure 3.1 illustrates the structures of the continuous and staged representations. The differences jump out at you immediately when you look at these structures. The staged representation utilizes maturity levels, whereas the continuous representation utilizes capability levels.

Figure 3.1: Structure of the Continuous and Staged Representations

What may strike you as you compare these two representations is their similarity. Both have many of the same components (e.g., process areas, specific goals, and specific practices), and these components have the same hierarchy and configuration.

What is not readily apparent from the high-level view in Figure 3.1 is that the continuous representation focuses on process area capability as measured by capability levels and the staged representation focuses on organizational maturity as measured by maturity levels. These dimensions (the capability/maturity dimensions) of CMMI are used for benchmarking and appraisal activities, as well as guiding an organization’s improvement efforts.

·         Capability levels apply to an organization’s process improvement achievement in individual process areas. These levels are a means for incrementally improving the processes corresponding to a given process area. There are six capability levels, which are numbered 0 through 5.

·         Maturity levels apply to an organization’s process improvement achievement across multiple process areas. These levels are a means of predicting the general outcomes of the next project undertaken. There are five maturity levels, numbered 1 through 5.

Table 3.1 compares the six capability levels to the five maturity levels. Notice that the names of four of the levels are the same in both representations. The differences are that there is no maturity level 0 and at level 1, the capability level is Performed, whereas the maturity level is Initial. Therefore, the starting point is different.

Table 3.1 Comparison of Capability and Maturity Levels

The continuous representation is concerned with selecting both a particular process area to improve and the desired capability level for that process area. In this context, whether a process is performed or incomplete is important. Therefore, the name incomplete is given to the continuous representation starting point.

Because the staged representation is concerned with the overall maturity of the organization, whether individual processes are performed or incomplete is not the primary focus. Therefore, the name initial is given to the staged representation starting point.

Both capability levels and maturity levels provide a way to measure how well organizations can and do improve their processes. However, the associated approach to process improvement is different.