Capability Maturity Model Integration (CMMI) is the new de-facto standard process improvement model for determining the organizational maturity in product or software development (Figure 2.5). Since many organizations would like to focus their improvement efforts across the disciplines within their organizations. In October of 1997, U.S. Department of Defense requested SEI to include the development of a common framework for supporting the future integration of other discipline-specific CMMI models (Figure 2.6). CMMI is an important model for product development industry.
Many procurers require a specific level of maturity from their suppliers. Also many companies set internal process improvement objectives driven by the maturity levels of CMMI.
Figure32.5: The frameworks quagmire
(Source: Sarah A. Sheard, Software Productivity Consortium 1997)
Figure42.6: CMMI History
(Source: Interpreting the CMMI: A Process Improvement Approach, April 2003)
A model is a simplified representation of the world. Capability Maturity Models (CMMs) contain the essential elements of effective processes for one or more bodies of knowledge. These elements are based on the concepts developed by Crosby, Deming, Juran, and Humphrey [8]. CMMI is an integrated model of many CMMs intended to achieve process improvement (Figure 2.7). CMM is a model that 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 [4]. CMMI models are not processes or process descriptions. The actual processes used in an organization depend on many factors, including application domain(s) and organization structure and size. In particular, the process areas of a CMMI model typically do not map one to one with the processes used in organization.
Figure52.7: CMMI derivation
(Source: Interpreting the CMMI: A Process Improvement Approach, April 2003)
CMMI defines five levels of organizational maturity in product development (Figure 2.8). Level 1 (initial) represents the lowest, and the level 5 (optimizing) the highest maturity. CMMI defines the maturity levels through process areas. By default, every organization is at maturity level 1. To reach level 2, an organization should satisfy the goals of seven process areas – such as Requirements Management and Project Planning. To achieve the level 3, an organization should perform all the process areas of the level 2 plus the process areas defined for the level 3 – such as Requirements Development and Technical Solution. Analogically, maturity levels 4 and 5 require the implementation of new process areas as well as those of the lower level process areas.
We describe as follows:
Figure62.8: CMMI maturity framework
(Source: Interpreting the CMMI: A Process Improvement Approach, April 2003)
z Maturity 1: Initial
At maturity level 1, processes are usually ad hoc and chaotic. The organization usually does not provide a stable environment. Success in these organizations depends on the competence and heroics of the people in the organization and not on the use of proven processes. In spite of this ad hoc, chaotic environment, maturity level 1 organizations often produce products and services that work;
however, they frequently exceed the budget and schedule of their projects.
z Maturity 2: Managed
At maturity level 2, an organization has achieved all the specific and generic goals of the maturity level 2 process areas. In other words, the projects of the organization have ensured that requirements are managed and that processes are planned, performed, measured, and controlled.
z Maturity 3: Defined
At maturity level 3, an organization has achieved all the specific and generic goals of the process areas assigned to maturity levels 2 and 3. At maturity level
3, processes are well characterized and understood, and are described in standards, procedures, tools, and methods.
z Maturity 4: Quantitatively Managed
At maturity level 4, an organization has achieved all the specific goals of the process areas assigned to maturity levels 2, 3, and 4 and the generic goals assigned to maturity levels 2 and 3. Sub-processes are selected that significantly contribute to overall process performance. These selected sub-processes are controlled using statistical and other quantitative techniques.
z Maturity 5: Optimizing
At maturity level 5, an organization has achieved all the specific goals of the process areas assigned to maturity levels 2, 3, 4, and 5 and the generic goals assigned to maturity levels 2 and 3. Processes are continually improved based on a quantitative understanding of the common causes of variation inherent in processes [3].
CMMI has two representations. One is the staged representation. The other is the continuous representation. In the staged representation, maturity level of an organization ranges from level 1 to 5. In the continuous representation each process capability level ranges from 0 to 5. The staged representation is most suitable for an organization that does not know which processes need to be improved first because the staged representation offers process areas applicable to each maturity level (Figure 2.9). The continuous representation provides flexibility for selecting processes fit for achieving business goal of the organization [5]. CMMI provides 25 process areas (Process area means a cluster of related practices in an area that, when implemented collectively, satisfies a set of goals considered important for making significant improvement in that area [4]. Goals are classified as generic goals and specific goals. A generic goal describes
the characteristics that must be present to institutionalize the processes that implement a process area. A specific goal describes the unique characteristics that must be present to satisfy the process area [4].
Practices are expected components for satisfying goals. Practices are classified as generic practices and specific practices. A generic practice is the description of an activity that is considered important in achieving the associated generic goal. A specific practice is the description of an activity that is considered important in achieving the associated specific goal [4].