Why it is called six sigma?

The monthly award could be a tribute to all of the charlatans out there who pretend to be adept at statistics.

seemes correct….a good idea

But why is it just 6 sigma, why cant it be 12 sigma … NASA operates on 12 Sigma…
is 6 the lucky number for bill smith ?
 
 

HUH?

12 sigma is 2 * (6 sigma).
Actually, you may have a fair question there, Stan.
If you’re asking whether I know just how high of quality a sigma level of 12 would be and how much it would cost to attain it, the answer (in layman’s terms) is really good and a lot.
If you’re suggesting that I didn’t answer the right question because sigma level is talking about standard deviations on one side of the process average so (some might think) 6 sigma could just as well have been called 12 sigma, then the answer is that sigma level refers to sigmas between process average and closest spec limit after adjusting for 1.5 sigma shift.
If 12 sigma means something different to you, maybe you can tell me about it.

I think you should read about Six Sigma prior to making the statements you have made.  Go to the “New To Six Sigma?” link on the top of the links to the left of this page and find out what Six Sigma REALLY means.
As for the spelling and grammer in this forum, in case you have not noticed, many if not most of the posters are not from the US or UK, so English is a second language and many of them are not very familiar with our colloquialisms and probably either use translator software (which is not very reliable) or are using this forum to practice and learn the language and about Six Sigma.
Of course, there ARE a few “good ol’ boy rednecks” on here who are “hukt own fonix werkt fer mee!” types.

I am not changing any definitions.
If you buy into the 1.5 shift nonsense, the highest sigma value that I have seen defined is 9.7 sigma which would be approximately  0.0000000000000001 DPMO.
Do you really think any one has achieved that or would even know how to measure it?
The stuff about NASA being 12 sigma is just a bunch of it. They are closer to 3.
You are trying to come off as an authority on this but you don’t even have a concept of what it means to be 6 much less 12 sigma.

shashi,
You need to complicate things a little more:
1. Six Sigma is a Breakthrough Strategy. Breakthrough is very different than control. Read Juran “Managerial Breakthrough” 1964.
2. Six Sigma is +/- 6 std deviations
3. 99.7 % is not 3.4 anything even defects. Do the math.
Good luck.

kbailey,
I do not agree that it is arbitrary.
If you take a look at the time SS started most people felt they were being pushed beyond anything reasonable by the Automotive industry asking for a Cpk of 1 (not that that was a huge issue but it was the mentality at the time). There was that moronic book “Quality is Free” that believed you could get perfect quality with posters and floor mats (actually if you sell enough books you don’t have to care any more). We knew that quality by exhortation didn’t work (Deming). you needed to better than 3 sigma and less than infinity.
If you get a copy of the Motorola chart that shows the relationship between opportunity count and sigma level you can see where it makes more sense from a complexity/capability combination than 3 or infinity.
Just my opinion.
Good luck.

Stan, I didn’t suggest you were changing definitions. I just wanted to make sure 12 sigma might have some special meaning I wasn’t familiar with.
I’m not disputing your statements about NASA or the apparent improbability of achieving a sigma level of 12. Practically speaking, I think it’s a bit unrealistic. However, if you had a process that’s performed often enough (like if lots of people would die from it), and if the cost of failure were high enough, and if the cost of preventing defect were low enough, you could conceivably want to set 12 as your sigma level target.
Before you just dismiss this, consider: CTQ’s can be so commonplace and expected that we don’t even state them. If I’m having a house built, I’m not going to tell the builder that one of my CTQ’s is that the roof has to stay up. If I were shopping for baby formula, I wouldn’t bother to check for radiation levels below a certain spec (although I can conceive of a world where that would be a sad necessity.) The reality is that we don’t actually bother to measure all of the true CTQ’s or opportunities for defects, simply because the cost (or bother) is too much to justify based on how confident we are in the quality with regard to that particular CTQ.
The relevance of this is that – especially in DFSS projects – we can’t assume that the customer’s stated requirements are comprehensive. If you don’t meet some requirement that they just assumed, you’re going to disappoint them badly.

Mike,
Your post touches on some of points which I would say support the claim that it’s arbitrary. As we get closer to 4, 5, and 6 sigma quality being more common in both manufacturing and transactional processes, the bar will rise.
I’m not sure if the chart I’ve seen is the same as the one you’re referring to, but the one I’ve seen shows that even 6 sigma isn’t really very good when you get into very complex products/processes with hundreds of thousands of opportunities for defects.

Using this definition of arbitrary from Webster.com: “based on or determined by individual preference or convenience rather than by necessity or the intrinsic nature of something”
Choosing to use the value six in Six Sigma may not have been arbitrary as in “arbitrary and capricious” but is was arbitrary in that it was convenient for Motorola at the time. It’s definitely not due to necessity or the intrinsic nature of something. If Bill Smith and others had been at some other company and dealing with transactional processes, they could just as well have settled on 4 sigma. If they worked in sales, marketing, or recruiting, they might even have settled on 1 or 2 sigma.
I think I understand about the 3.4 defects per million just fine. Short term, we measure the process and calculate a probability or projected defect rate. We don’t actually run off a million widgets (or opportunities) and count to see if we have 3.4 defects. A casual reader of the “New to Six Sigma” section isn’t going to get that.
The other thing they’re going to miss is that the way we measure processes and calculate sigma level is going to produce more than 3.4 defects per million. The 3.4 DPMO calculation doesn’t factor in the likelihood of special cause variation. What do we do when we identify special cause variation? Eliminate it, and then remove those data points from our control charts.
Your point #3 hits on the key: 80%-90% of the manufacturing organizations in the world today. Maybe it’s because of my background outside of manufacturing. Some people get too hung up on that six sigma level and 3.4 defects per million and they conclude Six Sigma methodology can’t apply to their processes where 95%, 75%, or even 50% success rates seem (and may very well be) unattainable. They need someone to explain to them that Six was a good level to settle on at the time for the people who were involved, but that as a name for a business strategy and quality methodology it’s arbitrary.

“In the early and mid-1980s with Chairman Bob Galvin at the helm, Motorola engineers decided that the traditional quality levels — measuring defects in thousands of opportunities — didn’t provide enough granularity. Instead, they wanted to measure the defects per million opportunities.”
Sounds to me like some necessary or intrinsic factors at play.
In your original posting, you seemed to imply that the six in Six Sigma was a number chosen at random.  You also said, “They need someone to explain to them that Six was a good level to settle on at the time for the people who were involved, but that as a name for a business strategy and quality methodology it’s arbitrary.”  But I still will stress that this was and is NOT an arbitrary figure that Motorola “settled on.”  Statisticians will tell you that the six sigma level of performance is attainable and the best figure to work towards in any process – manufacturing or other.
I do agree that the “required level” stated by management, sales, or the customer may be other than six sigma.  Some of these requirements may be arbitrary or out of misunderstanding of statistical analysis.  Some may be necessary due to regulations or citizenship (as in the safety issue.)  But you will not deter me, nor most of the others here, from the fact that Six Sigma is a methodology based on proven strategies backed by even more statistical evidence.  It is NOT arbitrary.
You do seem to have some statistical knowledge.  But you stated that the “casual reader of the new to six sigma section isn’t going to get (the probablilty vs. actual.)  Just as true is the fact that the casual reader of your original post will think that Six Sigma was just some figure a bunch of consultants pulled out of a hat and wrote a book about.

KB,
Yes the bar will rise that is why we doa thing called continuous improvement. Lets all try to get to six for a while.
Interesting interpretation of the chart. Lets turn that around. If it shows you how bad you will do (which it doesn’t) it also shows you why you need to be there to even be remotely viable if you have hundreds of thousands of parts. Then we can assess how many products have hundreds of thousands of parts.
Just my opinion.
Good luck.

Rubberdude,
Depending on the current process output vs. the desired customer requirements, the cost may be higher.
One thing I always say is that the business determines the need for increased sigma level through a Lean/Sigma project, not the GB / BB / Stats groups.  Don’t pay $1 more to increase the sigma level unless the return is significantly greater over a period agreed to by Finance.  If the process can support the customer specs, fine. If not,  evaluate the cost of attaining the required specs vs. the $ benefit and move it up the food chain.
 

I suggest that this type of question should be replied by ISIXSIGMA moderator. If there is so much confusion out there about the name of the program, then …..
Best thing is to look for a previous thread, read some material, and then ….
Why old standard is called 3 Sigma quality?
If you know the answer of this question then you know the answer of your question.

Your “intuitive knowledge” has failed you in the Six Sigma arena.  I suspect you do have an understanding of statistical analysis, but don’t know a lot about the Six Sigma system or how it works.
Yes, Stan does have a lot of knowledge and experience in Six Sigma.  And I won’t try to bull#### my way into making you believe I am an expert.  But I will say that many of the comments I see here come from misinformed people who have not read or studied the Six Sigma methodology and think it’s just another “flavor of the month.” and then, for some reason, want everyone else to think they know all about SS.
“Oh, ye of little faith….”

>many of the comments I see here come from misinformed people who have not read or studied the Six Sigma methodology and think it’s just another “flavor of the month.” and then, for some reason, want everyone else to think they know all about SS.
What does this have to do with my remarks? I thought we were talking about the name, not the value or longevity of 6 Sigma.

I think if you read your posting # 55243, my statement has EVERYTHING to do with your remarks……..

Rubber, I’m even more confused now.
I’m saying that Six Sigma also has great potential value in areas where a sigma level of six probably is never going to be attainable – including politics, sales, marketing, sports, etc. How does that tie to your comment about posters who see SS as a “flavor of the month?”
Six Sigma isn’t the end – it’s the means to the objective of competitive advantage and the goal of long term success. Either a) you’ll never reach a sigma level of 6 or b) you and the competition will both reach it. Six Sigma isn’t just about striving for a sigma level of 6 through DMAIC and DFSS, it’s also about redefining your CTQs and metrics based on what drives “customer’s” decisions and expectation levels in order to achieve competitive advantage – regardless of what you see as the “ideal” sigma level to aim for. If Six Sigma were just about striving to someday reach a sigma level of 6, then it would be a “flavor of the month.”

Mike,
Breakthrough strategy?
From times immemorial (and through common sense), we have used the familiar cycle of identifying a problem, putting metrics around it, making a CBA, brainstorming for solutions and finally implementing one (you would have done it too). We then put in reports and Incident reports etc to monitor the process and look for improvements. The people responsible have been those who want to get things done and are perhaps accountable for good performance. The management is always interested in good initiatives and they are being played as the villains for ever !
For the above processes, we have always used cause and effect (fishbone) diagrams, flow charts, histograms, pareto analysis, process maps, architecture diagrams, test models, SLA documents, training programs, market surveys etc.
What’s causing all the fuss. Is it the question of top management support? Is it the question of tools? Is it the question of techniques? Is it the question of jargon and buzzwords?
We have had all this before and we still have them. Do we mean to say that Six Sigma is different from what we already know? That we will be lost without the buzz words and the multicoloured belts?
Why not just do our jobs and minimise problems through the core concepts? (unless you need to join the jargon bandwagon). What do we need Six Sigma for? We are still doing it even without the label, right?
Manish
([email protected])

Manish,
Yes, breakthrough strategy. Before you start rambling about what all this fuss and time immemorial you need to go read about the difference between control and breakthrough. Rather than trying to sound like another one of those time tested hardened veterans who has seen it all you will find that it may be that little piece of information you missed that was documented in 1964.
Instead of telling everyone all about what you know take a couple minutes and read at least the first 2 chapters of “Managerial Breakthrough” by Juran. You will understand the difference.
I am not sure where the villianous management came from. I see a lot more damage done by the old guard and their tales of the good old days and all the stuff they did (not much in the way of hard tools in your list by the way – lots of that lovefest stuff though). It’s history and its business. Quoting Gordon Gecko “What have you done for me today sport?”
Good luck.

Tom,
Of course the cost will be higher. The minute someone looks at the process you have incurred additional cost. It isn’t about cost it is about Return on Investment (ROI). Why would anyone mindlessly charter a project without some idea of what it will cost versus what it will payback (even if it is soft dollars)? Every project should be a business decision before a “belt” sees it.
Good luck.

One of my favorite things about Six Sigma is that if companies do it right, they can eliminate most of the need to bring in those expensive consultants.
Instead, some management teams take the approach of cutting heads and driving productivity to the extent that the don’t allow their own people to spend any time on process improvement – let alone develop their knowledge and skills in that direction. Then they go out and bring in expensive consultants to figure out what they and their people could have figured out for themselves at a lower cost if they’d simply put together a plan and had the discipline to carry it out.
IMHO, this is a breakdown in leadership. Management, in such organizations, is too busy wheeling and dealing to actually lead – or otherwise effectively manage – their areas of responsibility.

I agree 100%.

Am I a consultant? I wish!

I WHISH. Kinda. Kinda not.
A previous supervisory position I had, about 95% of what my team did was reworking billing defects for both paper and EDI billing. My goal was to eliminate the need for us to exist. We never got to that point, but with some fair management support we did make some progress.
Good consultants should look at it similarly. Managers are never going to be perfect – they’ll always need outside resources to help them. It’s a question of whether the consultants are going to catch them a fish or teach them to fish.

KB,
If you want to be a consultant hang out your shingle. I see a lot of comments about it and there isn’t anything stopping you since you know how to do it “right.”
As far as expensive. What does that mean? There is investment criteria in every company I have worked with. As long as the payback is in line with anyother investment then it is not expensive. It is an investment just like anything else. We have made the offers to do deployments on every continent in the world today (except Antarctica) for a percent of savings. They measure the savings not us. There has never been a contract written by us yet.
There is a consulting company who wrote one (%of savings). They got stiffed when it came time to pay the bill because it was “expensive.”
We saw a project produce $18 million on an annual payback. The incentive scheme (not for consultants) was 1%. The company gets $18 million and the people get $180,000 to split for the team and it offended the sensibilities because it was percieved as “expensive.”
It is an old and tired song and dance. You don’t have to be a spectator. If you know how to do it right get in the game and show someone.

You are only confused by your own postings.  You keep saying things that contradict yourself.  You make a statement then when someone trys to correct you, you claim you already know that….. make up your mind.
I still don’t think you grasp the real concept of the Six Sigma methodology, but perhaps you just are just not as articulate as you should be.
Now…….I’m done with this subject.

I think we’re talking about the same thing. Regardless of what euphemism management uses, if it involves getting people to work harder, take shorter breaks, eat lunch at their desk while they work (or skip it completely), and/or work longer days – I call it driving productivity. In my book, boosting efficiency means that you improve a process to accomplish more with less actual work – not just less dollars.
For the record – wheeling and dealing to me includes legitimate selling and deal-making. If senior management is neglecting the parts of the business that actually deliver customer value, it’s a problem even if they are being ethical in their dealings.

That’s what happens when people search past threads for the info they’re seeking – as the forum rules instruct.

Mike,
Don’t get me wrong. I work with Six Sigma tools and  techniques too. And we have saved almost a couple of million dollars in the past year alone. I don’t doubt the value of it at all.
What I am questioning is the buzzwords and the “jargonizing” that has happened lately. I am observing that when I start to explain what needs to be done to newbies, I inevitably get started on stuff that is based on common sense.
And the bad side effect will be that the familiar tools and techniques that have now gained a linkage with Six Sigma may be devlaued.
Hope I explained it better now.
Manish