An Analysis of the Relationship Between CMMI vs Six Sigma

An Analysis of the Relationship Between CMMI vs Six Sigma
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What Is CMMI?

CMMI or Capability Maturity Model Integration provides organizations with goals and a set of expected practices needed to meet such goals in several disciplines. A group of industry, government, and software engineering Institute representatives have developed these goals and the expected practices by compiling the best practices of various capability models over the years.

CMMI has 5 levels that gage the extent of compliance with such expected practices.

What Is Six Sigma?

Six Sigma is a statistical based approach to business improvement that aims to eliminate defects as perceived by customer. The Six Sigma philosophy views everything as a process that has inherent variability and aims at containing such variability to 3.4 per million opportunities.

Six Sigma methods collect data and use statistical analysis to understand the extent of variation from the desired levels and drive decisions to improve the processes by eliminating variability.

Difference Between CMMI and Six Sigma

What is the difference between Six Sigma and CMMI?

CMMI and Six Sigma are two of the best improvement-oriented initiatives, with many overlaps. A fundamental difference, however, exists between CMMI and Six Sigma. When comparing CMMI vs Six Sigma, CMMI is domain specific, Six Sigma is not.

The basic difference between CMMI and Six Sigma pertains to the scope of application. CMMI aims at process improvement in specific disciplines or process areas. The base model of CMMI caters to 22 such disciplines or “process areas.” Six Sigma, on the other hand aims at solving specific product or process related issues within the context of overall organizational process improvement. Thus, while CMMI is a domain specific improvement engine, Six Sigma has a much wider application, serving as both an enterprise governance model and a tactical improvement engine cutting across domains.

Relationship Between CMMI and Six Sigma

CMMI and Six Sigma should not be in competition. Simultaneous implementation of these concepts in an organization produces a synergy that helps in the successful accomplishment of company goals in a faster, better, and cheaper way.

Some companies use integrated process architecture to integrate CMMI and Six Sigma. Such integration could take four approaches:

  1. Implementation of CMMI to the highest level to establish systems and processes based on established best practices. Then, these practices are followed by implementation of Six Sigma to fine-tune such processes based on customer expectations and to continue with needed improvements.
  2. Implementation of Six Sigma as the governance model first, followed by using CMMI to close problematic gaps in process infrastructure.
  3. Simultaneous implementation of CMMI and Six Sigma by using CMMI to identify critical process factors and deploying Six Sigma frameworks in such critical factors, or using Six Sigma to identify areas where CMMI is required.
  4. Implementation of CMMI Level 3 to establish defined processes and then establishing Six Sigma to seek higher CMMI maturity levels. Six Sigma enables the successful implementation of CMMI, or accelerate the transition from one CMMI level to another.

The best approach depends on the organization’s circumstances.

A comparison of CMMI vs Six Sigma dispels many myths regarding these concepts competing against each other. A basic difference in approach notwithstanding, CMMI and Six Sigma compliment each other while ignoring the possible synergy resultant from using these concepts in tandem leads, which prevents a company from duplicating efforts.


  1. Siviy, Jeannine M; Penn, M. Lynn, M. & Harper,Erin. (December 2005). Relationships Between CMMI and Six Sigma. Software Engineering Measurement and Analysis.
  2. Siviy, Jeannine M.; Penn, M. Lynn; & Stoddard, Robert, W. (2007). CMMI and Six Sigma: Partners in Process Improvement
  3. Siviy, Jeannine M.; Penn, M. Lynn; & Stoddard, Robert, W. (February 2008). Integrating the CMMI and Six Sigma: Strategies. Retrieved from

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