Effects of Process Maturity on Development Effort

There is a good deal of anecdotal case-study evidence that organizations that have improved their SEI-CMM process maturity level have been able to reduce the amount of effort it takes them to produce a given software product. However, these case-study projects have concurrently realized other improvements in such areas as tool use, domain knowledge, component reuse, and office efficiency. As a result, managers have had no way of determining how much improvement is due to process maturity versus the other factors. This paper reports on several analyses in which the effects of process maturity were broken out from the other effects via calibration of the COCOMO II software cost estimation model. Using a 112-project sample a change in one level of process maturity resulted in a reduction of development effort from 10 to 32 percent. Using a 161-project sample a change in one level of process maturity resulted in a reduction of development effort from 4 to 11 percent.