What is Six Sigma? How is it used, and what does it have to do with the CMM? November 27, 2009

What is Six Sigma? How is it used, and what does it have to do with the CMM?

Developed by Bill Smith at Motorola in 1986, Six Sigma is a management philosophy based on removing process variation. It was heavily influenced by preceding quality improvement methodologies such as Quality Control, TQM, and Zero Defects. Six Sigma is a registered service mark and trademark of Motorola Inc. As of 2006, Motorola had reported over $17 Billion in savings from their own employment of Six Sigma practices throughout their global enterprise. Early corporate adopters of Six Sigma who achieved well-publicized success through the application of six sigma best practices to their enterprises included Honeywell (previously known as AlliedSignal) and General Electric, where Jack Welch famously introduced and advocated the method. By the late 1990s, about two-thirds of the Fortune 500 organizations had begun Six Sigma initiatives with the aim of reducing costs and improving quality.

My own professional experiences with Six Sigma began in the early 1990’s (I had first read about it in a Forbes magazine article in 1988) when I worked in manufacturing environments at Mercedes-Benz USA’s plant in Tuscaloosa (Vance), Alabama as well as Phipher Optical Wire Product’s plant in Tuscaloosa, the same city where the University of Alabama is located. It was in these environments where I was tasked with learning about six sigma and spent many hours in classrooms and factory floor and management workgroups implementing and training for a six sigma blackbelt. Six Sigma Black Belts operate under Master Black Belts to apply Six Sigma methodology to specific projects. They devote 100% of their time to Six Sigma. They primarily focus on Six Sigma project execution, whereas what are known in the Six Sigma universe as Six Sigma Champions and Master Black Belts focus on identifying projects/functions for Six Sigma.

Implementing a Six Sigma program in a manufacturing environment means more than delivering defect-free product after final test or inspection. It also entails concurrently maintaining in-process yields around 99.9999998 percent, defective rates below 0.002 parts per million, and the virtual eradication of rework and scrap. Other Six Sigma characteristics include moving operating processes under statistical control, controlling input process variables as well as the more traditional output product variables, and maximizing equipment uptime and optimizing cycle time. In a six sigma organization, employees are trained and expected to assess their job functions with respect to how they improve the organization. They define their goals and quantify where they are currently, their status quo. Then they work to minimize the gap and achieve “six sigma” (in a statistical sense) by a certain date.

Six Sigma focuses on the control of a process to ensure that outputs are within six standard deviations (six sigma) from the mean of the specified goals. Six Sigma is oftentimes implemented using a system with which I have worked many times: define, measure, improve, analyze, and control (DMIAC). Sometimes this same system is referred to as define, measure, analyze and control, or DMAIC.

Define means to describe the process to be improved, usually through some sort of business process model.

Measure means to identify and capture relevant metrics for each aspect of the process model. I have been in classrooms where this is referred to as “Goal -> Question -> Metric”.

Improve obviously implies changing some aspect of the process so that beneficial changes are seen in the associated metrics, usually by attacking the aspect that will have the highest payback.

Analyze and Control means to use ongoing monitoring of the metrics to continuously revisit the model, observe the metrics, and refine the process as needed.

Although some organizations apparently strive to use Six Sigma as a part of their software quality improvement practices, the issue that often arises is finding an appropriate business process model for the software development effort that does not devolve into a highly artificial simulacrum of the waterfall SDLC (Software Development Life Cycle) process.

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I’m Paul Seibert, Editor of Boston’s Hub Tech Insider, a Boston focused technology blog. You can connect with me on LinkedIn, follow me on Twitter, even friend me on Facebook if you’re cool. I own and am trying to sell a dual-zoned, residential & commercial Office Building in Natick, MA. I have a background in entrepreneurship, ecommerce, telecommunications and software development, I’m the Director, Technical Projects at eSpendWise, I’m a serial entrepreneur and the co-founder of Tshirtnow.net.