Thursday, February 23, 2012

Zero Defects and Six Sigma



This article begins with a quote from Deming in the New Economics: “Conformance to specifications, zero defects, Six Sigma Quality, and all other (specification-based) nostrums all miss the point.”

In  addition a good history of the Crosby contributions to Zero Defects and quotes from Dr. Juran on Six Sigma are included. The paper finishes with the Taguchi Loss Function and Deming's System of Profound Knowledge.

Lost to history is the experience of Ford with the Batavia Plant where they were making exactly the same transmission as Mazda. This provides a real life example of the difference focusing on meeting specification versus manufacturing to target (Taguchi's idea). Both outputs from Mazda and Ford were within specification. However, the Ford transmissions had twice the customer problems as the Mazda transmissions. VP John Beti famously remarked, "While we were busy meeting specifications, they were busy making them all the same." If you have never seen this video produced by Ford, it is worth the time. It is less than 12 minutes long.


Ford at first elected to close the Batavia plant. This caused an outbreak of cooperation between the management and the union. It took the plant 8 months to match the quality of Mazda.

Harry Truman once remarked, "History does not repeat itself. We just keep making the same stupid mistakes."

Deming warned us in 1993 before he passed: : “Conformance to specifications, zero defects, Six Sigma Quality, and all other (specification-based) nostrums all miss the point.” Since his passing we now have a world wide movement that is back to focusing on specifications.

2 comments:

  1. As the U.S. has moved away from manufacturing, we have been told that we have moved to a knowledge economy. If so, it is an even scarier thought for those of us who work in high-tech and other knowledge industries. Why?

    Speaking from knowledge of the software development industry, we lack even adherence to specifications. Specifications in software, often called designs, are often little more than intellectual exercises. What happens? The specification becomes a suggestion, and the developers become superstars or heroes for subverting the suggestion. No one holds the original designers accountable for (possibly) bad design that cannot be built. Nor do they hold developers for bad implementations of designs. Or any of the permutations of design (good or bad) and development (good or bad) that can come out of such a process.

    If a machinist or industrial engineer produced a running engine, when a transmission was requested, it would not be celebrated. If an engineer designed an unbuildable transmission, no one would ignore their failure to produce a proper design.

    One of the major challenges we face going forward is that software has become an essential hardware to the running of a business and the economy. We have a perspective on software that is incredible.

    Go take a look at the reported bugs for any software company (IBM, Microsoft, Apple, etc.). If they were producing transmissions of the same quality as their software, they would be out of business.

    How can I say this? Surely 99.99% of all software bugs are trivial and do not amount to anything significant for most customers. YES! This is correct. But, when your transmission goes wrong, it doesn't clean out your bank accounts, and release your customer's critical and confidential information to identity thieves.

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    1. Great addition Bill! Really like the last paragraph! Best, Cliff

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