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Matthew Barsalou

Six Sigma

Lean Six Sigma: 10 Objections and Answers

Can we stop calling it a fad now?

Published: Tuesday, October 13, 2015 - 11:37

I gave a rather successful talk on communicating design of experiments (DoE) at the recent ENBIS 14 conference in Linz, Austria. Things went mostly well, but it’s also fair to say many attendees had one major criticism: I didn’t explain why one factor at a time testing (OFAT) isn’t ideal. That oversight helped me realize how fortunate I am when it comes to lean Six Sigma. I no longer find myself having to explain what it is or why it can be beneficial.

Things were different in the past. I frequently heard criticisms about both Six Sigma and lean Six Sigma, and I often found myself attempting to justify them. Here are 10 common criticisms I used to hear as well as rebuttals to each.

It’s just a fad

No, it’s not. Six Sigma dates from the 1980s, and many of its tools go much farther back. Lean Six Sigma combines many useful tools together in one tool set, along with a systematic approach based on define, measure, analyze, improve, and control (DMAIC). A fad bursts onto the scene, gets credit for doing wonderful things, and then disappears before the supporting evidence is in and evaluated. But the evidence for the effectiveness of lean Six Sigma is here, and it’s still very much around.

We’re too small

A full-time lean Six Sigma staff with a Master Black Belt, 10 Black Belts and many Green Belts would be absurd in an organization with only 20 employees. A small company with turnover in the hundreds of thousands of dollars per year shouldn’t expect a lean Six Sigma project to yield millions of dollars in savings. However, this doesn’t mean that a small organization wouldn’t benefit from implementing lean Six Sigma projects. Ignoring inefficiencies and waste is leaving money sitting on the table. All organizations, regardless of size, should be pursuing continuous quality improvement, and lean Six Sigma offers a proven methodology for achieving that. Projects can be implemented on a part-time basis if the organization can’t support a full-time Six Sigma staff.

Lean Six Sigma is only for impressing customers

Lean Six Sigma is customer-oriented, but not just to impress the customer. It’s intended to deliver value to the customer. This in turn is expected to result in a financial advantage for the organization. Customers may be impressed to learn that an organization is using lean Six Sigma, but this is just a side effect and not the main intent.

We don’t need it

This argument probably predates lean Six Sigma by decades. I’m not old enough to have firsthand experience, but I suspect quality managers have been hearing this excuse since the first quality departments were formed. “Quality management? Statistical process control? Sampling plan? Inspection? Check gauge and fixture? We don’t need those.” Oddly, nobody ever says, “Customers? We don’t need them.” But that does seem to be the message. You may not see a need for quality improvement, but your competitors might.

Customers don’t ask for it

Your customer shouldn’t need to ask you to deliver a quality product or service, lower your costs by reducing waste, or tell you to stay competitive. These are things you need to do.

Can’t afford large investments

Research by Pulakanam Venkateswarlu has shown that lean Six Sigma leads “to an average savings of 1.7 percent of revenues over the period of implementation, and an average return of more than $2 in direct savings for every dollar invested on Six Sigma.” Can’t afford to invest $20,000 for a $40,000 return? Then start small, and scale up as successful projects are completed.

OK, but do it on your own

No. I admit that a simple “no” might not be the appropriate answer when an executive gives you the green light provided you do the project on your own. However, there is no other realistic answer. Your project will be doomed to failure without management support, and that failure might be used as evidence against you in the future: “Your last project failed, so there’s no point in trying again.” This is a conversation that you can only lose, so change the conversation.

You should no longer be pleading, “Please, sir, may I have a project?” You need to switch gears and start explaining why management support is a critical aspect of a lean Six Sigma project. The history of quality is littered with improvement initiatives that floundered and failed due to lack of management support. The quality tools and statistical methods used predate Six Sigma, so what’s different? Lean Six Sigma offers a structured approach and requires the support of top management.

We tried other methods, and they didn’t work

Obviously, you didn’t try the right ones. Or maybe they didn’t have support? This statement is difficult to counter only because there’s so much unsaid that lies behind it. What methods were tried? Was it a half-hearted attempt at quality improvement? Was it even a method or just a quality awareness campaign culminating in the unveiling of a sign stating something along the lines of “you are responsible for quality, so stop making mistakes?” You can’t effectively respond to such criticism without knowing what actually happened in the past. Get the details.

The 1.5 Sigma Shift is dubious, so Six Sigma doesn’t work

The claim that certain concepts in the early teachings of Six Sigma are wrong, such as the inherent 1.5 sigma shift in processes, and therefore lean Six Sigma is permanently flawed, is much like a straw-man attack that focuses on weaknesses while ignoring the strengths. Six Sigma has been credited with many drastic improvements during the last 30 years despite some of these maligned notions. Implementing a lean Six Sigma program doesn’t depend on understanding or even being aware of the 1.5 sigma shift and other earlier teachings. Clearly defining objectives, using quality tools, systematically collecting and evaluating data, and then acting on the conclusions are the key critical concepts that have withstood the test of time and can lead to quality improvements. In the end, the results are what count, not potential flaws in the theory.

Six Sigma only works in American companies

Readers based in the United States will probably not encounter this argument, but I have heard it several times while overseas. Granted, there are cultural differences between countries, but the underlying statistics work the same no matter where in the world they are applied. This argument seems to be the foreign equivalent of the old American “not invented here” stigma. Six Sigma has been found to be effective in Taiwan, India, Mexico, The Netherlands, France, and Jordan, as the references listed below attest. I think we can safely say lean Six Sigma, like its unfounded criticisms, is international.

• Cheng, Jung-Lang. “Six Sigma and TQM in Taiwan: An Empirical Study.” Quality Management Journal 14 No. 2: 7–18. 2007.
• El-Banna, Mahmoud. “Patient Discharge Time Improvement by Using the Six Sigma Approach: A Case Study.” Quality Engineering 25, No. 4: 401–417. 2013.
• Kumiega, Andrew; Davis, Michael; and Van Vliet, Ben. “Perspectives: Bank on It.” Quality Progress 46, No 6: 30-37. 2013.
• López, María de los Angeles Tlahuiz; and Burguete, Esteban. “Change for the Better.” Six Sigma Forum Magazine 9, No. 3: 20–24. 2010.
• Van den Heuvel, Jaap; Does, Ronald J. M. M.; and Bisgaard, Soren. “Dutch Hospital Implements Six Sigma.” Six Sigma Forum Magazine 4, No. 2: 11–14. 2005.
• Venkateswarlu, Pulakanam. “Costs and Savings of Six Sigma Programs: An Empirical Study.” Quality Management Journal 18, No. 1: 7–22. 2012.
• Wise, Adam. “India-Based Life Insurer Improves Customer Retention Through Six Sigma, Quality Tools.” 2014.


About The Author

Matthew Barsalou’s picture

Matthew Barsalou

Matthew Barsalou is a statistical problem resolution master black belt at BorgWarner Turbo Systems Engineering GmbH. He is an ASQ-certified Six Sigma Black Belt, quality engineer, and quality technician; a TÜV-certified quality manager, quality management representative, and quality auditor; and a Smarter Solutions-certified lean Six Sigma Master Black Belt. He has a bachelor’s degree in industrial sciences, and master’s degrees in engineering, business administration, and liberal studies with emphasis in international business. Barsalou is author of Root Cause Analysis, Statistics for Six Sigma Black Belts, The ASQ Pocket Guide to Statistics for Six Sigma Black Belts, and The Quality Improvement Field Guide.


OK then, how about “irrelevant” in place of “dubious”?

Perhaps I should have said “irrelevant” in place of “dubious.” It is 2015; we should not even be having this conversation.

I reread my article and I did not see any reference to the validity of Six Sigma’s six sigma. It was simply not addressed. However, if you would like proof of some form, please see the references listed at the end of the column. The resulting savings in hard cash is what matters, not origin of the sigma shift.

Six Sigma's six sigma

The 1.5 Sigma shift/drift/correction is not "dubious" as you euphemistically claim.  It is fabricated, pure and utter nonsense.

These articles describe the origins of the Six Sigma nonsense in detail:http://www.qualitydigest.com/inside/six-sigma-article/six-sigma-lessons-...http://www.qualitydigest.com/inside/six-sigma-article/six-sigma-lessons-...

As Dr Wheeler puts it "a triumph over common sense".  If you suggest there is some validity to Six Sigma's six sigma, please prove it to us.


The 'Shift'; Just Say No

Dubious:  adjective

1. hesitating or doubting

2. not to be relied upon, suspect

I think Matthew was succinct in basically saying that it is a 'concept' that should not be relied upon without being abrupt or rude.  And he effectively stated that thse shift's veracity is irrelevent.  He seems not to care about the statistical aspects of the name "Six Sigma", which has reached the level of Kleenex as a 'generic name' for Quality Improvement philosophies, methods and tools.  Most people* have simply moved on from the whole 'six sigma 1.5 sigma shift' thing.  As Matthew points out, it isn't relevent to improving quality, so it isn't worth the time to discuss it or attempt to prove or disprove it again (and again and again and again).  Life is just too short to get upset about a side issue. 

I've attended the last several years of the ASQ Lean Six Sigma Conference and I didn't hear or see a single reference to the shift.  People were simply focused on finding practical approaches that would work for them.  If we are going to champion Quality Improvements perhaps we are better served by focusing our efforts on the real issues we face, such as understanding the difference between enumerative and analytical statistics and diagnostics strategies that provide alternatives to fishbone diagrams and 'brainstorming'.   Let's give people practical tools and methods that they can use instead of telling them the old mythical horse is dead...

*the only exception being companies in India who seem to have just discovered the old writings but they too will find their way out of the statistical desert...Some people won't get it of course, but we'll never change their minds so I choose to focus on what I can do...

I applaud your efforts to

I applaud your efforts to address the various myths surrounding Lean Six Sigma. As the author of The Six Sigma Handbook and the owner of an online Lean Six Sigma training company I frequently receive emails with the general theme of "Lean Six Sigma is Dead." Forbes has created a minor industry on the subject going back at least a decade. This must be the only fad that is going on 30  years old.

But you didn't answer the question

Matt - very nice article that addresses the 'yeah-buts' of Lean Six Sigma...

Just wanted to point out (tongue in cheek) that you didn't explain why OFATs are bad.  :)