The CMM is also developed by the Software Engineering Institute (SEI). It is a model for judging the maturity of the software processes of an organization and for identifying the key practices that are required to increase the maturity of these processes.

The SEI maturity framework consists of five levels:

1. Initial: this is where most organizations begin. A level one process is usually ad hoc, few processes are defined and success depends more on individual effort than team work;
2. Repeatable: basic project management processes are implemented to follow cost, schedule and functionality. The process is sufficiently defined to be able to repeat earlier successes on projects with similar applications;
3. Defined: the processes for both management and engineering are documented, standardized and integrated into a standard organizational software process;
4. Managed: this level requires that detailed measures are taken of the process and product, and that process and product are quantitatively understood and controlled;
5. Optimizing: continuous process improvement is in place, using quantitative feedback.