Connecting Software Industry Standards and Best Practices: Lean Six Sigma and CMMI

Integration of Six Sigma and the Capability Maturity Model Integration (CMMI) is becoming fairly widespread, yet confusion remains about their relationship.

Part One of this article includes several case studies that answer some of the more common questions,

Part Two describes the relationship of Lean Six Sigma and Six Sigma's approach to improvement of existing products and processes (Define, Measure, Analyze, Improve, Control [DMAIC]),

and Part Three examines the relationship between Design for Lean Six Sigma (used to develop new products and processes or major enhancements) and the CMMI Engineering Process Areas.
http://www.stsc.hill.af.mil/crosstalk/2007/02/0702GackWilliams.html