Staged Versus Continuous Models

Staged models - Staged models are comprised of a number of distinct levels of maturity. Each level of maturity is further decomposed into a number of processes that are fixed to that level of maturity.
The processes themselves are staged and serve as foundations for the next process.
Likewise, each level of maturity is the foundation for the next maturity level. The Software Engineering Institute’s Capability Maturity Model is a prime example of a staged model.

Continuous models - In the continuous model, processes are individually improved along a maturity scale independently of each other. For example, the project planning process could be at a much higher capability level than the quality assurance process. ISO/IEC TR 15504 (SPICE) is an example of a continuous model.