Lean vs. Six Sigma Debate (Sadly) Rages On

As many of you know, I’m a passionate advocate of Lean management practices and the power of Lean in transforming organizations. So I grow weary when I hear people characterize Lean in a way that is worlds apart from what Lean really is. My view has always been (and will likely always be): if you’re not well-versed in a subject, better to ask questions and learn than spread untruths in a world that desperately needs to operate from a more fact-based place.

Today I ran across yet another irritating piece on the ongoing Lean v. Six Sigma debate. I’m never irritated because I want Lean to “win” the debate. I’m irritated because it shouldn’t be a debate at all.

The piece by Kyle Toppazzini, “Lean Without Six Sigma May Be a Failing Proposition,” appeared in the Monday edition of Quality Digest’s Quality Insider column.

I’ll let you read the article yourself. I posted this response:

Hi Kyle – I appreciate your attempt to make a case that organizations HAVE to use Six Sigma in conjunction with Lean but that’s simply not true. The methodologies CAN be used together (if very well thought out), but they don’t HAVE to be used together. It seems that you’re missing quite a number of key Lean principles, practices, and tools in your characterization of “Lean.” The ED outcome you have described is decidedly NOT a Lean outcome. Quite the contrary.

You pose a key question: “So why do some lean advocates feel compelled to consider one process improvement framework only?” As a “lean advocate,” let me share my reasons:

1. Because of its holistic and systems-thinking perspective that, when deployed correctly, avoids the sub-optimization you describe in your article. I agree that “shot gun Kaizen events” are wrong, but let’s avoid throwing the baby out with the bath water. Kaizen events done right are tied to a systems improvement strategy, such as a VSM. Yes, there are a number of Lean novices out there that are doing the “wrong thing.” But that doesn’t mean that’s how Lean is designed to be done. “Lean” does not equal “kaizen events.”

2. Because of its root-cause orientation – I don’t even know how to respond to your comments about Lean and RCA. What you say is simply not true. Why do you think Lean is used merely for “simple” problems? I wouldn’t classify any of my clients’ problems as “simple.” In fact, in the white collar space, the problems are often monumentally complex and multi-faceted.

3. Because of its emphasis on standardization – Again, what you say is simply not true. Lean is ALL about creating process stability and predictabilty. Where do you get this idea that it’s not?

4. Because of its accessibility and people-orientation. Lean’s approach to business management (it’s not all about process design) is inconclusive and heavily focused on learning. So, for example, a skilled Lean practitioner is not a “do-er.” Rather, he/she coaches, teaches and facilitates to spread problem-solving and improvement capabilities across an organization as quickly and deeply as possible.

HBR can include articles and posts until the cows come home about how Lean cannot possibly be a standalone method for improving business performance. All that accomplishes is providing additional data points to support my hypothesis that many previously reputable publications are falling prey to printing opinion versus fact. Because the facts do indeed prove otherwise.

When I sold my recently published book, The Outstanding Organization, to McGraw-Hill, they pushed hard for me to include the word “Lean” in the title or subtitle. But I lobbied hard to NOT include the word because I wanted my message — we need to improve how we improve — to rise above the Lean vs. Six Sigma debate.  While there are fundamental differences in how Lean and Six Sigma have evolved, they both originate with the teachings of W. Edwards Deming, Joseph Juran and others.

But somehow many people have missed the boat with Lean. They have no idea what Lean really is, but they continue to spread untruths that confuse executives and new improvement professionals alike. Which doesn’t serve anyone in the end.

I’m curious to know your thoughts. Why do you think this debate rages on? What will it take for it to end?

by Mike Sporer reply

Maybe executives would be less confused if they thought about “lean” as a mind-set, not simply a process one can follow. Six Sigma seems to me like a methodology, not a mind-set.

Many people also confuse subtraction with mind-numbing cutting. They should read Matt May’s books before jumping to any conclusions.

I utilized a lean, subtractive mind-set as a second in command. I can’t show someone how to lead with that mind-set; because it is indeed a way of thinking, not just a way of doing.

    by Karen Martin reply

    Hi Mike – Yes, I also view Lean as overall mindset and management approach vs. solely a problem-solving approach as Six Sigma is typically used.

    As you’ve likely seen on the back and forth on the comments to the blog post I cited, the larger problem is that many of the people out there talking about Lean simply don’t know what it is. Remember that it’s Jack Welch who made Six Sigma sexy and he was VERY far from being a Lean Leader.

    Matt May hits the nail on the head with his work. I attempt to do so in my latest book as well tkmg.wpengine.com/the-outstanding-organization. Matt’s next book, The Laws of Subtraction is his best yet!

      by Mike Sporer reply

      Just finished Matt’s book…you are right, best work yet! I especially liked the after-chapter short articles, including yours. And I wholeheartedly agree with your comment on Welch.

by Matthew E. May reply

Pretty silly article. Borders on irresponsible agenda-pushing by Quality Digest writers. Walk into a Toyota (inventors of lean) facility and ask them to show you all their six sigma projects and meet their black belts. Good luck with that.

    by Karen Martin reply

    Silly indeed. It’s a shame that irresponsible “journalism” gets printed because novices have no grounds by which to reject the fallacies being purported.

      by Mark Graban reply

      And Amen to Karen. I complained loudly to “Quality” Digest that they shouldn’t be giving a platform to the clueless (at least being clueless about Lean).

    by Mark Graban reply

    Amen to Matt’s comment

    by H W M reply

    Silly indeed, while it works if applied and implimented correctly — of course. Might I suggest a quicker and more effetive method, pick up and throw away all the time and paper trails to prove out the problems real people just don’t have time and companies the money involved. Doctors solve life and death problems in a quick and simple method. Identify a problem, get three/four people together (maniger/worker/engineer), if agreed on a fix impliment it–if not get bigger group in sit down — still if no fix put it on a list to come back to until solved, go back and see if fix works in a week or two if not fix it again until solved (small paperwork time foot print) problem/solution agreed on by three people/impliment/follow up…follow up…revolving until fixed…Small quick simple forget the ever ending paper trials and time consumming junk! Workers know where the problem are that make their life difficult and want to make them better – trust me! Just don’t give them a t-shirt give them money for it, then their ears will really perk up! Can’t eat a t-shirt! If I solve a problem that cost me 100,000 a year and they save me from it flip them 25,000 you just saved 75,000 that year and 100,000 in comming years….and just improved the quality of a persons life!

by Mark Graban reply

Karen, the Quality Digest post you’re referring to (and this whole discussion) isn’t about Lean vs. Sigma. It’s about knowledge versus ignorance.

There are many people online (and LinkedIn) who regurgitate the nonsense taught to them about Lean in their “Lean Sigma” belt training.

Six Sigma statistical methods have their place (Matt is right that Toyota doesn’t use Six Sigma, they’ll say they use the 7 basic QC tools), but my real beef is the misinformation and B.S. that’s spread about Lean being “just about efficiency” or Lean just being “a toolbox” to use when people see fit or Lean just being 5S.

    by Karen Martin reply

    My beef as well, Mark. Unfortunately much of this is borne from an adult style version of the “gossip game” I played as a kid – the story keeps changing and getting diluted the more people tell it and don’t confirm the presumed facts they’re passing on.

    If only people were more knowledgeable about and accepting of the fact that it takes 10 years to achieve mastery in any endeavor. The only plausible outcome from a single week of Lean training in a belt program is heightened awareness and beginning skill development–nothing more. It takes intensive study and practice for a significant period of time and I’m often shocked by how little people in improvement roles have read and continued learning via conferences, workshops, etc. That’s the problem, I believe, with certifications, belts, and anything else that implies competence that simply isn’t there. Thanks for your comment.

by Jonathan Hall reply

Thanks for fighting the food fight for Lean. It is a shame that there is a battle to begin with.
I agree with you when you stated, “how little people in improvement roles have read and continued learning via conferences, workshops, etc. That’s the problem, I believe, with certifications, belts, and anything else that implies competence that simply isn’t there.”

What is the Lean industry doing to be able to certify competence? Is there a group of Lean leaders that is working on a standard, comprehensive, and rigorous program to validate Lean Competence? I worked for years with PMI to become a certified Project Manager. It is an achievement that has meaning and respect throughout the world. We need to establish something similar in the Lean Industry.

    by Karen Martin reply

    Jonathan – Thank you for your comment. There is, in fact, a reputable certification program that’s jointly managed by ASQ, AME, SME, and Shingo. The Body of Knowledge upon which the test is based is sound and it’s the only “true” Lean certification in my mind.

    That said, I see two significant limitations with it: 1) the content is heavily manufacturing oriented, and 2) it’s still merely a notch on one’s belt that may or may not reflect proficiency, let alone mastery. I’m a bit of a purist in terms of the roots of Lean and how valuable and necessary the intense teacher-student relationship is. Certifications only test book knowledge and the level of success on one project. Nothing more. Unfortunately, the label may give the uninitiated a false sense of security. But it may beat taking someone’s word for their skill set! At least the certification reflects a person who has studied and thought about Lean in a structured way.

      by Mark Graban reply

      Karen – the ASQ/AME/SME/Shingo certification (I think beyond the initial bronze level) does require more than a test – in the demonstration of a Lean portfolio or demonstration of putting the methods to use beyond book knowledge.

        by Karen Martin reply

        Yes, I realize that. I mentioned the project.

          by Mark Graban

          Ok I missed that… my fault for multitasking with the World Series game. But the certification is not “nothing more” than the exam. I guess I got off track with that earlier statement.

          by Karen Martin

          We may have to agree to disagree here. In my book, proficiency is determined through far more than what certification’s assess. This is a long-standing view of mine that pre-dates Lean certifications. As I said, it may beat nothing, but I stand by my belief based on experience that people go gaga over people who are certified who are not able to perform at the levels the certification implies to the uninitiated. Enjoy the World Series! Who ya routing for?

by Mark Graban reply

We are in agreement. I think you need more than just a test and exam. I had misread your comment… you can just delete my comments if you like, but I thought your original comment wasn’t clear enough in stating that AME/etc. was more than just a test.

    by Karen Duddy reply

    Very interesting dialogue. I have been recently “belted”…CLSSBB blah, blah. The education was very useful…both the Six Sigma and Lean portion. As my previous sentence suggests, the content was taught separately, so it’s been up to me to figure out how to integrate. Briefly, it’s very simple when you focus first on “learning to see”. If I am able to get that part right, the next steps and tools seem to emerge. Without being able to really look at a value stream and integral processes…I’m lost. I do like some Six Sigma-esque tools for process capability and monitoring, but takt time is just as useful. DMAIC and DMADV are nice formats, but the A3 has become my more favored working tool. Point is, in my opinion, if I ever aspire to consider myself an improvement professional, I am obliged to keep informed and continuously improve how I improve.
    On being belted…it may have been a great mistake. Might as well have just painted a bullseye on my forehead, back…name your body part. While the idea was to have an “expert” (really?) help process owners improve their processes, the reality was that they could now step back (which would have required them to have actually stepped in at some point) and I would just fix it.
    While I am an idealist, I’m not naive. I figured this would happen, but I couldn’t pass up the educational opportunity! To summarize: 1. I agree with all your points and am always buoyed by your ongoing passion for improvement 2. I appreciate learning about all improvement frameworks and methodologies, and feel it is my obligation to know when and how to use these powerful tools 3. No one wins when improvement methodologies face off in battle. When we use all our power and knowledge and focus on making the customer be the winner…then we all win. Mark, Karen, Matthew…thank you for your perseverence. We are indeed listening.

      by Mark Graban reply

      Thanks for sharing your experience, Karen. That seems to point to the need for groups to just offer CSSBB and CLBB certifications as two separate things, if this truly isn’t being taught as a integrated methodology.

      That’s why I think of it as Lean And Six Sigma, not “Lean Sigma.”

        by Karen Martin reply

        Thanks, Mark. Along with my book-related campaign, “multi-tasking doesn’t exist,” I’m going to add another “Lean Sigma doesn’t exist” — it’s Lean AND Six Sigma. Right on.

          by Mark Graban

          You’re not battling against thousands or tens of thousands entrenched “Certified Multitaskers” on that front, at least.


          by Karen Martin

          Ha! Not say that too loudly…a new certification will surely crop up! :-)

      by Karen Martin reply

      Thanks, Karen, for sharing your thoughts. I feel your pain about the bullseye thing. All too often, organizations “annoint” experts so they can do all the work, which is the antithesis of adopting Lean business practices. Tomorrow’s webinar — We’ve Had It All Wrong: Manage Processes, Not People — will hit this point hard. All certification and belt programs need to place a strong emphasis on developing the expertise MERELY to be effective coaching it. We all need to coach and teach far more than we “do.”

by Mark Graban reply

Tigers fan, from my childhood, by the way.

by Tim Pettry reply

Karen, I’m coming to this a little late, but really appreciate the perspectives of everyone contributing to the discussion.

Karen Duddy, I appreciate your “target” story. I grew up in a plant that started with Lean, having utilized the talents of ex-Toyota Georgetown managers to teach us and put a system for improvement in place. That plant won the Shingo Prize based upon our success in engaging all employees in improvement. Imagine UAW workers timing their own processes, creating their own Standard Work documents and using those documents to launch a new product and adjust staffing levels when production volumes rose, then fell. They got “it”.
Unfortunately, our corporate folks turned our production system into a corporate check list of things to do, rather than create a corporate atmosphere of continuous improvement. Our quality folks brought Six Sigma on board, offered promotions, stock options, etc. and developed quality “experts”. When these experts went to the floor to gather the data they needed for their projects, the workers turned on them and told them to do it themselves since they were getting paid the big bucks to solve problems. It’s not the tool that creates the resentment, its the approach to using it that does. There wasn’t much leading with humility when it came to our approach to introducing Six Sigma. If utilized in the right context, Six Sigma is an excellent approach to addressing major process and design problems.

Karen, thanks for the plug for the AME/ASQ/Shingo Prize/SME Lean Certification. Mark is correct in pointing out that there is more to the certification than the test and 1 project. In addition to passing an exam that is based on the body of knowledge, candidates must also have a certain number of hours of training that ties back to the body of knowledge and submit a portfolio of 5 projects that demonstrate their ability to apply the knowledge they’ve gained. At the Bronze level, the projects are tactical (area/departmental) in scope. At the Silver level, there is a mix of 3 tactical and 2 integrative (value stream) projects, as well as a mentoring piece that is added. The idea being that once you’ve attained the Silver level, candidates have a responsibility to those who are following them to coach and mentor them appropriately. Finally, at the Gold level, the mix of projects shifts to 1 tactical, 2 integrative and 2 strategic (overall organizational transformations). There is also an interview process at the Gold level that is on the level of a job interview.

As for the bias towards Manufacturing, it does exist, however, I’ve been working as a member of the Oversight and Appeals committee to change that. I found that when I came into Healthcare, there was not much interest from Healthcare professionals to read the manufacturing books. The same can be said for other administrative functions. We’ve been through the exam questions and have tried to modify the questions to be more generic in nature and worked to get Mark’s book, Lean Hospitals, to be included on the recommended reading list that test questions are pulled from. It’s not a perfect program, but then again, that’s what continuous improvement is all about. Feedback like yours is very helpful to making the program more robust.

    by Karen Martin reply

    Hi Tim – Welcome to my blog! Thank you for your comments and pointing out that the Lean Certification process requires a portfolio of results and projects vs. one project. I still stand by my views that certification is often mis-interpreted to mean that someone has achieved a level of mastery that they simply haven’t. That said, it is a way to demonstrate a level of commitment to learning and practice that is valuable.

    Thank you for carrying the torch with the Certification team about the need to address some non-manufacturing concepts that are differently applied outside of manufacturing. Most of Lean is the same outside manufacturing, but some Lean concepts need to be applied quite differently, due to environmental differences. Many people are guilty of black-and-white thinking: Lean’s exactly the same in office/service or Lean’s wildly different in those settings. It’s the nuanced differences that matter for successful application of Lean principles, practices and tools in non-manufacturing–and it takes a deft hand to become proficient in knowing what and when to flex. As you move forward with incorporating some of the non-mfg nuances, please don’t forget other industries such as energy, financial services, government, retail, food service and hospitality, I.T., etc.

    While I’m thrilled that Lean is now “mainstream”–at least conversationally–in healthcare, my new concern is that now Lean’s all about manufacturing and healthcare. I work with many industries who are rapidly adopting Lean practices and those people may want to become certified as well.

      by Tim Pettry reply

      Karen, your blog, like the rest of your work is a pleasure to read. Thanks for sharing!

      Based on your comments, I believe we are in violent agreement! I would love to hear more from the other industries about their successes and challenges in implementing a Lean mindset.

        by Karen Martin reply

        Thank you for your kind words, Tim. Yes, it’d be nice if the successes and challenges of other industries were more widely known. I hear about it all the time as I work with so many other types of orgs and I “hang” with others who do the same. The variety in my client list — tkmg.wpengine.com/clients — is fairly representative of range of industries who have adopted Lean practices, at least in pockets. There’s a lot going on in construction, financial services, energy, government, distribution, technology, etc.–and has been for 5-8 years now. More and more orgs discover Lean each year. Of course, most don’t accomplish much with it– but that’s the subject for another day! :-)

by Scott Rutherford reply

Karen, to pick a nit but didn’t Lean predate Deming & Juran? Understand and agree with the blog message.

    by Karen Martin reply

    Hi Scott – Thanks for your comment. Lean is the result of Toyota’s adoption of the principles of Deming, Juran and a few others–and our intrigue with how Toyota operates so successfully and consistently.

by Ricky reply

The debate should definite continue into eternity. Why? Because we should never ever stop thinking and improving understanding. My take on Lean v 6Sigma comes from a behavioral perspective. Success is driven by our ability to create the desired performance behavior at all organizational levels. In choosing we need to consider which of the two has the best fit to the maturity level, readiness and organizational culture. And perhaps more important, what is the customer complaining about – quality or that he is not getting the service/product fast enough. In practice you might find the customer is happy with quality but irritated with waiting. Then Lean is more appropriate and less complicated to comprehend. If your quality levels are acceptable to the client, it will most probably cost you an arm and a leg in money and effort to raise it slightly. You will gain much more client satisfaction and loyalty by minimum effort and investment in Lean by reducing Lead time. I guess I’m advocating a horses for courses approach, app posed to forcing a philosophy onto a situation. Our success will be our ability to match the right improvement approach to the situation, rather than enforcing a fixed believe and mid-set onto a situation.

    by Karen Martin reply

    Thank you, Ricky, for your comment. It seems that you may not fully understand Lean and may be one who believes that Lean addresses speed problems and Six Sigma addresses quality problems–which is very far from the truth. Lean is an all-encompassing management approach that is founded, first and foremost on delivering high quality. We measure speed as a means to assess both speed itself AND quality, because you can’t deliver quickly if you don’t deliver high quality at each and every step of a process. This false differentiation – Lean addresses speed, Six Sigma addresses quality – also leaves out what Lean is REALLY about and that’s people development, a characteristic that many in the Six Sigma community have also missed. Please don’t misunderstand – I turn to “Six Sigma” tools when heavy analysis is needed. But many, many (indeed most) organizational performance problems can be solved without the “big guns” that heavy analysis provides.

    Lean is a full spectrum business management practice. It’s not merely a set of waste-reduction, speed-enhancing tools. It involves leadership practices, measurement practices, problem-solving practices, value stream and process management practices, and other necessary practices for outstanding performance such as delegating authority with boundaries to the frontlines, engaging in deep and regular reflection, frequent visits to where the work is done (go and see, going to the gemba), etc.

    I assert that success will occur when organizations begin to adopt Lean FULLY and have a few — a FEW — specialists available to help with deep statistical analysis when it’s needed. And that’s nearly always in settings when there’s a very narrow band of tolerance (e.g. issues involving magnetism, electrical conductivity, solutions, ballistics, thickness of various materials, projectile needs, air quality, etc.). Many organizations will simply never have that need.

by Scott Rutherford reply

Karen, please forgive me if my comments are already covered by others. What ticks me off is how Lean pundits complain about how Lean is misunderstood and yet do nothing to truly understand Six Sigma. Six Sigma is ALSO a philosophy that requires systems thinking and all the other conceptual “goodness” that your colleagues associate with Lean. If I wanted to describe one difference between the two philosophies it is quantitative vs qualitative measurement. You need both, each philosophy tends to rely (almost used the word lean!) on one more than the other.

What I find hilarious is how Lean consultants bemoan the lack of purity some of their competitors placing in trying to brand their offerings as a way to distiguish themselves. I personally don’t care about tags. I try to fully understand capabilities so I can recommend approaches that fit situations. I think if more Lean consultants do that, it may resolve the issue that you are describing.

My 2 cents.

    by Karen Martin reply

    Well, Scott, we’re just going to have to agree to disagree. You’re dead wrong in characterizing Lean as being about “qualitative” measurement. Dead wrong. If anything differentiates the two approaches, it’s the outcome each seek to achieve: project completion vs. building problem-solving proficiency throughout the organization.

    That said, many organizations have not adopted Lean the way it was intended and is most powerful. Many have cherry picked “waste reduction” as thought that’s the essence of Lean. Whoever taught you Lean also potentially suffered from a misunderstanding about what Lean is and what it is not. There are far too many well-intended but misguided “teachers” out there. If you truly want to understand Lean, I recommend you reach the classics thoroughly–especially the entire Toyota Way series. It’s also important to read both A3 management books and Toyota Kata to understand the fundamental means to building deep improvement proficiency across the entire workforce. Lean isn’t something one learns in a 4-week green belt program. It’s an entirely different way to manage a business from its people to its products to its processes to its accounting systems to its customers to its suppliers — all with the ultimate goal of providing greater customer value.

    Bottom line: Lean isn’t a “brand.” It’s a sensible, practical, accessible, and highly effective business management approach.

      by Scott Rutherford reply

      Karen, I will agree that Six Siigma uses projects as their vehicle for change. But Six Sigma has the same intent as Lean; to build an organizational culture of improvement. As you rightly point out, both have similar roots. It is all about the execution. I think you proved my point in the last paragraph of my previous post.

by Andy Dobson reply

Karen, I can’t count the number of times I have heard people refer to emaciated as ‘Lean’! People just don’t know what good looks like!

    by Karen Martin reply

    So true, Andy. The fitness analogy works really well – A person with a lean body isn’t unhealthfully skinny – he or she has a low-ish percent body fat that’s ideal for health. He or she is also very strong and flexible. Weak and skinny doesn’t work! Thank you for your comment.

by Sadique Salim reply

Great discussion.

My only point is lean is nothing but a set of tools, six sigma is nothing but a set of tools. Yes, both of them have mgt goals cascading down etc. So we have two setd of tools. So just use the tool which is more appropriate in a particular problem be it defect or waste. If i have two sets of tool boxes, i would be happier because i would feel more prepared. All together, 50 tools may be? Why fight? Learn 50 and apply when it is required.

I am considering people and project mgt skill similar in both cases*

    by Karen Martin reply

    With all due respect, Sadique, Lean is far more than “nothing but a set of tools.” It’s a holistic management system that, yes, has some tools that, when applied effectively, produce outstanding results. But it’s the management practices that give Lean its power. Traditional Six Sigma doesn’t include the management practice component, which is one reason why so many people try to combine the two.


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