Software Engineering Institute

Evaluating the reliability of maturity level ratings is crucial for providing confidence in the results of software process assessments. This report examines the dimensions underlying the maturity construct in the Capability Maturity Model (CMM) for Software (SW-CMM) and then estimates the internal consistency (reliability) of each dimension. The analysis is based on 676 CMM-Based Appraisal for Internal Process Improvement (CBA IPI) assessments conducted during the period of January 2000 through April 2002. The results suggest that the SW-CMM maturity is a three-dimensional construct, with Project Implementation representing the maturity level 2 key process areas (KPAs), Organization Implementation representing the maturity level 3 KPAs, and Quantitative Process Management representing the KPAs at both maturity levels 4 and 5. The internal consistency for each of the three dimensions as estimated by Cronbach's alpha exceeds the recommended value of 0.9. Although more should be learned about the distinctions between maturity levels 4 and 5, the internal consistency of those KPAs is comparable to those at levels 2 and 3.