Six Sigma is very good at detecting variability and its root causes; historically, it was about undesirable forms of variation and removing them and their associated costs. Detractors of Six Sigma (and proponents, too) will say, "Six Sigma really isn't anything new. Most of this stuff has been around for years! The people at Motorola just integrated it all into a more coherent and systematic model." Yes, modern Six Sigma is the result of an evolutionary process, and not some wildly creative invention that caused a revolution in quality methods across corporate America.

 

Is it true that Six Sigma really started at Motorola in 1986? As a corporate program for the systematic reduction of variation in Motorola's manufacturing plants - yes it is true. Why did Motorola create it? Competitive pressure, particularly in the Asia-Pacific region on the telecommunications business, provided a crisis that stimulated the creation of Six Sigma. Too many defects were escaping from Motorola's manufacturing plants, producing large scrap and re-work costs, excessive warranty costs, and painful losses in market share. But Motorola was not the first to create an approach to being systematic and data-driven during the control of variation in a manufacturing process.

The clearest systematic, statistically-based starting point was way back in the bowels of Western Electric, where a clever man named Walter Shewhart documented what we now call the methods of Statistical Process Control - SPC. According to Wikipedia, when Dr. Shewhart jointed the Western Electric Company Inspection Engineering Department at the Hawthorne Works in 1918, industrial quality was limited to inspecting finished products and removing defective items. That all changed on May 16, 1924, when Dr. Shewhart prepared an approximately one-page memorandum outlining the essential principles for what we know today as process quality control. Dr. Shewhart's work pointed out the importance of reducing variation in a manufacturing process and the understanding that continual process adjustment in reaction to non-conformance actually increased variation and degraded quality.

Dr. Shewhart's approach; Measure samples of data from a manufacturing process, Analyze the data using statistical methods, Improve the process when it moves off-target and finally, Control the process after putting it back where it was supposed to be by using a documented plan. So, the steps M-A-I-C existed way back in the early 20th century. By the way, if you look into it all, you will find the Improve step stimulated incredible amounts of innovation to find a way to put the process back where it belonged! One more example of necessity being the mother of invention.

From there, the path evolves to the documented methods of Total Quality Management (TQM), with Shewhart, now at Bell Telephone, mentoring additional founding fathers, the most notable being the cantankerous W. Edwards Deming. Shewhart and Deming promoted a cycle of quality actions that contained 4 continuous steps; Plan, Do, Check and Act. As time went on, other leaders such as Juran, Ishikawa and Crosby became famous proponents. Then, in 1986, Bill Smith and his contemporaries at Motorola coined the name and now-famous methods of "Six Sigma". It was Motorola that defined a corporate culture based upon a step-by-step, statistical approach to problem solving. They focused on hard data, as opposed to the softer skills and methods of TQM.

Since then, its application has been extended beyond Motorola and the factory floor to business processes, technology development, product design, systems engineering and even research in a variety of companies and settings. Lean principles have been linked to Six Sigma (Lean Six Sigma), as the two methodologies mutually enhance each other's impact on waste and cost reduction. In an effort to prevent problems, Design for Six Sigma has been adopted by many product development organizations.

 
Six Sigma's strategy to deal with variation must continue to evolve. The future of Six Sigma, whatever name we might call it, has less to do with bad effects of unwanted sources of variation, and everything to do with the desired forms of variation that help us innovate and prevent problems before they happen.