Let's fix Six Sigma!

[Steve Prevette]

Having reignited the fire storm, I suppose I should comment.

I still believe that Six Sigma, at least as defined by Mikel Harry and "Cowboy Quality" is fatally flawed, and I have made that statement and details elsewhere. I do understand that many folks are embarking on their own spins on Six Sigma, but that still begs the question - what is six sigma?

But let's go to a positive side. Here is what I believe in.

I do believe you need to be grounded in theory and be able to document your basic approach to life, the universe, and everything. I believe that I have grounded myself with about 70% Deming, 10% Tom Peters, 10% Ackoff and 10% Operations Research. Thus I am fairly predictable. If you ask me to do something, you know what you are going to get. A set of control charts and Pareto charts.

Now certainly with an O.R. degree I am knowledgeable of several tools beyond SPC. But it is rare that this level of complexity is needed. Yet I do believe we need to stay at least at the level of SPC in order to bring in the understanding of stable versus unstable processes.

I do tend to try to make use of data on hand, the owners have paid for it and ought to get something out of it. But we do still need to design new data sources in some cases.

Yes, "it depends" and "context" are important. But I believe we need some underlying core principles (such as SOPK) or we become an amorphous blob just slinging around keywords and tricky phrases, and not accomplishing much beyond "tampering".

At least I'll say this has worked for me.

 

[bobdoering]

Yes, "it depends" and "context" are important. But I believe we need some underlying core principles (such as SOPK) or we become an amorphous blob just slinging around keywords and tricky phrases, and not accomplishing much beyond "tampering".

We have seen where people have looked to "core tools" as rubber stamp implements. Understandably so, the way they have been forced onto people. Core principles....perhaps. Core tools...sorry, one size does not fit all. Have to get past that...

Think outside the box..or they will screw the lid on and drop you in a hole.

 

[M Greenaway]

Re: Just another thought

Now don't all jump down my throat but is anyone interested in ISO developing a standard (or more than one!) on six sigma?

Your thoughts?

What purpose would this serve ?

 

[Stijloor]

Re: Just another thought

What purpose would this serve ?

Consistency of interpretation and practice perhaps? I am not opposed to the intent of Six Sigma, but the name itself it has become an almost meaningless label used by anyone who claims to have found a better Six Sigma mouse trap.

Stijloor.

 

[Jim Wynne]

Re: Just another thought

Now don't all jump down my throat but is anyone interested in ISO developing a standard (or more than one!) on six sigma?

Your thoughts?

I think it's a great idea. ISO should also develop an astrology standard.

 

[M Greenaway]

I guess it would be good to have some standardised method of reporting defect rates, and other process measures - much like the international accountancy rules that we have (is it IFIR's - excuse me if the acronym is incorrect ?).

I find that much of Lean and Six Sigma is more to do with creative accounting than real process improvement - much like the criticism Frederick Taylor came in for all those years ago when he introduced his concepts of 'scientific management' at the Bethlehem steel plant - the similarities are quite scary !

 

[artichoke]

I guess it would be good to have some standardised method of reporting defect rates,

This is impossible. Defects relate to where the specification has been placed. The specification can be anywhere you wish. Even Bill Smith stated that defects can be reduced by widening the specification.

Forget about counting defects (unless there is absolutely no other alternative). The control chart is the best measure of process quality.

I find that much of Lean and Six Sigma is more to do with creative accounting than real process improvement

Absolutely !!

 

[M Greenaway]

I dont quite understand your statement that my concept is 'impossible'.

My sentiment comes from one of the Six Sigma core concepts, that of DPMO.

I know that many companies who traditionally reported a defect rate of lets say 3%, got into the Six Sigma stuff, looked at all the 'opportunities for error' as the new denominator in their defect rate calculation, and then came up with a ppm figure based on that.

No process improvement had occurred, just a simple change in the metric.

Also with no clear description of either what constitutes a defect, or what constitutes an opportunity for a defect, the concept is somewhat open to abuse one might suspect ??

 

[Jim Wynne]

I dont quite understand your statement that my concept is 'impossible'.

My sentiment comes from one of the Six Sigma core concepts, that of DPMO.

I know that many companies who traditionally reported a defect rate of lets say 3%, got into the Six Sigma stuff, looked at all the 'opportunities for error' as the new denominator in their defect rate calculation, and then came up with a ppm figure based on that.

No process improvement had occurred, just a simple change in the metric.

Also with no clear description of either what constitutes a defect, or what constitutes an opportunity for a defect, the concept is somewhat open to abuse one might suspect ??

What makes it impossible in practical terms is that even if you could come up with some sort of standard formula or method, everyone would have to agree to abide by it in earnest, and books that are now considered private would have to opened up. It's much easier to use constructions that are open to multiple interpretations, but look good on paper.

 

[artichoke]

I dont quite understand your statement that my concept is 'impossible'.

My sentiment comes from one of the Six Sigma core concepts, that of DPMO.

Perhaps I can help you understand.

DPMO is the core six sigma concept. A defect occurs when a product or service is outside specification.

• Now who sets the specification for a particular process, product or service ?
• If someone else set the specification, would the specification be the same ?
• Do customers and manufacturers always set the specification at the same points ?

As Bill Smith, the hero of six sigma, ironically pointed out, the specification can be anything you want it to be. DPMO can hence be anything you want.

It has been a great line for consultants approaching senior managers to say "I can absolutely guarantee that I will reduce your defect rates ! " How how impressive is that ... at least for anyone who has no understanding of the basics of quality. Approaches such as this have been used to milk companies of billions of dollars.

Counting defects and the specification based methodology is indeed the fundamental flaw in six sigma. The dozens of other flaws in six sigma follow. My papers give details.