Although they both share a focus on quality and customer satisfaction and are designed to accomplish different things, CMMI and Six Sigma can actually work together.
“The two technologies work really well together. Six Sigma wants you to map out your processes (Process Mapping), but it doesnâ€™t actually tell you what the processes should be. CMMI determines the right processes for an organization to start. However, an organization may have to tailor it or add to it to make it work for them. CMMI provides the process backbone that Six Sigma needs,” says Jeannine Siviy, senior member of the technical staff at the Carnegie Mellon Software Engineering Institute.
Six Sigma Improving CMMI Framework
Six Sigma : Your Resource for Strategic Management. Meikah Delid. Eversun Software 2006.