A five-level model for assessing the capability and maturity of software development organizations. It was developed by Watts Humphrey at the Software Engineering Institute and the first version was released in 1987. The level of an organization is assessed in terms of key process areas and key practices.

Level 1, the initial level, is characterized by lax procedures and lack of management appreciation of software issues. At level 2, the repeatable level, basic procedures are defined and there is sufficient discipline to enable earlier successes to be repeated; there is, however, no framework for improvement and the risks associated with new and different developments are high. The defined level, level 3, is the level at which all software development projects in the organization use a documented and approved version of the organization’s process for developing and maintaining software; in addition, there are procedures in place for maintaining the process model. At level 4, the managed level, detailed measurements of process and product quality are collected and analysed, so that the causes of changes in process performance can be identified. The last level is the optimizing level, characterized by steady process improvement arising from the feedback obtained from the projects.

After 1997 CMM was subsumed into Capability Maturity Model Integration (CMMI), which extends its concepts to other types of organization.