Since all CMMI models have a common architecture sharing 16 core process areas and a common rating system, using more than one model is comparatively easily accomplished. The SEI is working to make use of multiple models even easier since many users can derive benefit from each of the available models.

Below are links to more information about using multiple CMMI models for process improvement:

Using CMMI-DEV and CMMI-SVC Together, a presentation by Alex Stall and Eileen Forrester of the SEI, describes combined approaches and patterns for using multiple models in mixed service and development environments.

CMMI V1.3: Combining Acquisition, Development, and Services, a blog post by Ben Linders, describes how users can pick and choose from the process areas in all three CMMI models to create a tailored set of best practices.

Multi-Constellation/Model Tutorial, a presentation by Rawdon Young and Alex Stall of the SEI, describes the concept of multi-model improvement, which enables businesses to tailor a CMMI model for themselves that is consistent with their business goals.

Leveraging CMMI-ACQ and CMMI-DEV to Improve Supplier Performance, a presentation by Kileen Harrison and Anne Prem of Booz Allen Hamilton, describes using multiple models for process improvement and the results they achieved.

Multiple Simultaneous Appraisal Experience, a presentation by five people from TATA Consultancy Services and Software Technology Transition, explains the concept of a multiple simultaneous appraisal, in this case using CMMI-DEV and CMMI-SVC.

Applying CMMI-SVC Process Areas to CMMI-DEV Projects, a presentation by Lynn Penn of Lockheed Martin Corporation, explains how some process areas in the CMMI for Services model can benefit development organizations.

There are other methods, standards, and technologies that comprise CMMI Compatibility.