Has Six Sigma been a failure?

My response to the message, Has Six Sigma been a failure? (broken link was removed) on the Deming Electronic Network email list (DEN).

I think Six Sigma has been a success. Do I think it the best option? No, I would prefer a Deming based approach. But I think Six Sigma can be a successful improvement strategy. Like most any management strategy, many applying it do so poorly (hacks as Deming would say). But if most any DEN participant worked with the leading thinkers in the Six Sigma community you would find they fit very well within the community of the DEN, though with some distinguishing traits.

To varying extents the Six Sigma thinkers might not accept the level of importance we place on certain items, things like: “joy in work,” co-operation (vs. Competition), the need to change the organizations culture, the importance of unmeasurable factors, or eliminating performance appraisals. But the best minds (as I see it) in the Six Sigma community share our beliefs, to a large extent. The approach they have taken is to work with the current culture more than most of us would like, if we could instead have the culture move toward a more Deming based culture.

Many Six Sigma proponents have done great things: Gerry Hahn, Roger Hoerl, Soren Bisgaard, Bill Hill, Ron Snee, Forrest Breyfogle. They happen to all be statisticians, I believe; as were most (though not all) of those who taught with Deming. I think there is a connection. Statisticians that follow the applied statistics school of thought fit very well with Deming’s ideas, and with the good practice of Six Sigma.

I am biased, however. My father worked with George Box, who I see as a leading figure in the applied statistics community. They wrote (along with Stu Hunter) Statistics for Experimenters which is heavily used in good Six Sigma efforts. The second edition was recently published (the first edition was published in 1978). I grew up with the ideas of applied statistics and Deming’s ideas.

I believe part of the distrust of Six Sigma is because many efforts are done poorly and deserve criticism. In addition, the general Six Sigma community believes things I disagree with. The whole 1.5 sigma shift idea is not sensible. The name of the effort is not good. But, many of us (or if that is not accurate, then at least me) who have to try and convince others to practice Deming’s ideas find the “System of Profound Knowledge” less than an ideal name. The whole percentage failure example theme is silly (if we accept just 99.4% success that means 15 doctors will drop the baby they deliver every day).

Six Sigma efforts are missing some import ideas that would improve it, in my opinion. Still, I would rather take a good Six Sigma effort and then add more of Deming’s ideas than take a company that has not had any such effort (just like I would like to build on a good
implementation of “TQM” or Lean Thinking…).

Read several good articles by Roger Hoerl.

You can also see more articles, by those I mentioned above as leading Six Sigma thinkers, via the Curious Cat Management Improvement Library:

John Hunter

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9 Responses to Has Six Sigma been a failure?

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  6. Calvin.K says:

    I agree with you, six sigma is a very good improvement and problem solving tools but the whole 1.5 sigma shift idea is not sensible. Other than that, six sigma is not really concern about the cost. Therefore, personally i prefer lean six sigma

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  8. Daniel Lang says:

    John, it has been over 6 years since you posted this article. Reading it for the first time it is hard to get out of how you answered your rhetorical question and state that SS is a success. You distrust and disagree with SS and yet is a success. It seems you were walking the tight rope. I happen to see SS as an overemphasis on statistics and management by numbers/objectives. The latter in direct contradiction to Dr Deming’s Point 11 which I wholeheartedly agree with. Yes, statistics are needed, but not their overemphasis and misuse.


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