Resolving Different Approaches of CMMs

The definition of a capability maturity model allows the community to develop models having different approaches. As long as a model contains the essential elements of effective processes for one or more disciplines and describes an evolutionary improvement path from ad hoc, immature processes to disciplined, mature processes with improved quality and effectiveness, it is considered a CMM.

All of the source models for CMMI are considered capability maturity models; however, each has a different approach. Review and examination of each source model led to the discovery of two types of approaches to presenting capability maturity models. These types of approaches have been given the label "representations" in the process improvement community. A representation reflects the organization, use, and presentation of components in a model.

All capability maturity models have process areas that are defined by levels.^[2] An example of a process area is Project Planning. There are two types of CMMI model representations: staged and continuous.

^[2] Two of the source models use other terms for the concept of a process area. The Software CMM uses the term key process areas; the SECM uses the term focus areas.

The staged representation is the approach used in the Software CMM. It is an approach that uses predefined sets of process areas to define an improvement path for an organization. This improvement path is described by a model component called a maturity level. A maturity level is a well-defined evolutionary plateau toward achieving improved organizational processes.

The continuous representation is the approach used in the SECM and the IPD-CMM. This approach allows an organization to select a specific process area and improve relative to it. The continuous representation uses capability levels to characterize improvement relative to an individual process area.

CMMI supports both representations because of the familiarity that people had with the source models and the concern that if one representation were selected over the other, part of the community would not adopt CMMI. Although this adds complexity to CMMI, it also provides an easier transition to CMMI for people familiar with one representation or the other.