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Kyle Toppazzini

Six Sigma

Lean Without Six Sigma May Be a Failing Proposition

Don’t put all your eggs in one basket

Published: Monday, September 24, 2012 - 16:07

In a Harvard Business Review article Tom Davenport writes, “I hope that when companies start getting excited again about process improvement, they resist one method for doing so. A hybrid, combined approach is really the only approach that makes any sense. In religion many people worship only one god, but in process management we should all be pantheists.”

Recognizing that a single approach to process reform is unwise, selected U.S. government departments have implemented lean Six Sigma with great success. (Lean Six Sigma is a combination of two process improvement frameworks, lean and Six Sigma, aimed at improving time, quality, and cost of delivering products and services.) In an article posted in Forbes called, “Lean Government Six Sigma? Why Do Politicians Ignore It? the author, Kellen Giuda writes, “The Department of Defense is trying to duplicate the outstanding results seen by the U.S. Army and Navy implementations of lean Six Sigma in 2005 and 2006 when they saved a combined $2.45 billion as of 2008.” 

The private sector has also recognized that the blend of lean and Six Sigma has significant benefits. The same Forbes article that cited benefits to the U.S. government from the implementation of lean Six Sigma also states that 3M, ACME, Sears, Dell, DuPont Whirlpool, and Xerox have all benefited from implementing this methodology.

So why do some lean advocates feel compelled to consider one process improvement framework only?

The short answer is that lean can result in improved quality and costs, not just optimization of business process flow.

Lean advocates are likely to tell you that continuous incremental improvements to your process will result in greater and more sustainable improvements to your organization as compared to a one-time process transformation—or at least they should. Lean advocates may also tell you that lean does address quality through methods such as mistake-proofing the process or root cause analysis. I would not disagree with these arguments.

Lean, however, can use techniques such as a kaizen event which is a planned process improvement effort that enables a small group of people to improve some aspect of their process quickly. The kaizen event may then be repeated throughout the organization. To ensure an organization continues to improve, a continuous improvement process may be put in place. Unfortunately, an enterprise is more complex, consisting of interrelated processes, systems, and people. For example, a lean intervention may be designed to lower wait times in a hospital emergency room; however, without addressing the complete patient flow, once the patient has moved from the ER, the patient may spend up to six or seven hours waiting to see an emergency doctor. This is clearly not a holistic solution that results in a positive hospital experience.

There are other reasons why lean, in isolation, may not be the best remedy for your organization. Those reasons follow.

Other reasons lean in isolation may not be optimal

1. A lean intervention does not always eradicate the root cause of your problems. Lean is a great tool for addressing the root cause of a known process problem. Generally speaking, the source of the problem is localized and contained within one part of the process.

In a lean intervention, the tools at your disposal will enable you to design or redesign a process that is streamlined, simplified, has mechanisms in place to prevent errors, and is supported by a culture of learning and continuous improvement. This is great, but what happens if the source of the problem is more complex and is unknown? What happens if the problem you identify in the lean engagement is temporary?

To better answer these questions, a more statistical approach must be undertaken; this is where Six Sigma tools come into play. Failing to address the root cause of the problem properly with the right tools may result in the problem manifesting itself in other parts of the process.

2. Lean does not equate to process stability and predictability. Implementing lean will not ensure your process becomes more stable and predictable. Although a skilled lean consultant will ensure that the new process is standardized, this does not result in a stable process. You can have a standardized process with a great amount variation in results. I remember one organization that aimed to serve 95 percent of its clients within 45 minutes. The problem with this target is that 5 percent of the clients can be served within five hours and the organization would still consider itself successful. Imagine if that 5 percent of clients who were served within five hours told 20 other people, or if that information was released by the media; the effects on the organization could be devastating.

Six Sigma techniques are capable of designing processes that are free of such variation. In the previous example, a more appropriate target might be that 95 percent of the clients will be served in 45 minutes, and no customer will wait longer than 65 minutes. By having tightly defined parameters, it will also be easier for an organization to anticipate what is required to meet customer expectations.

Other considerations beyond lean Six Sigma

Even lean Six Sigma has its limitations, limitations that could be better addressed in combination with other management frameworks. In large organizations like governments, it is likely that you will need to consider additional factors not necessarily considered in a lean Six Sigma engagement. These factors may include:
The ability for the organization to absorb change
Strategic alignment
Organizational structure
Political risk
Supply chain optimization

For example, an organization may design an optimal process that gets bogged down in the decision-making process that is a result of how the organization is structured. The organization may fail to consider the current and past resource depletion, which may result in a failed transformation exercise. If the process improvement initiatives do not contribute to the organization’s strategy, it will likely not get the senior management support needed to move forward.

For this reason we must consider all elements that affect a process.

Closing thoughts

In a recent article in the Ottawa Citizen, a columnist talks about all the benefits of going lean for Canadian government departments. This article fails to consider all the risks of considering one—and only one—methodology to create sustainable efficiencies within the government or any organization. As Davenport points out, “A hybrid, combined approach is really the only approach that makes any sense.”

Unlike my lean counterparts, who will tell you that lean is an afterthought in the lean Six Sigma engagement, I adopt a customized approach that best fits the organization’s challenges. What do you think? Does it make sense to put all your eggs in one basket, or does it make sense to look at hybrid approaches to process improvement?


About The Author

Kyle Toppazzini’s picture

Kyle Toppazzini

Kyle Toppazzini is the president of Toppazzini and Lee Consulting, and an international leader and consultant in lean Six Sigma. He is a certified balanced scorecard trainer and a lean Six Sigma Black Belt. He works with C-level executives to assist in developing and implementing process improvement strategies and transformations that result in faster, better, and more cost-effective delivery of services and products. Toppazzini’s Lean Six Sigma Challenge has appeared in more than 200 outlets, including Yahoo News, Business Week, The Wall Street Journal, The Boston Globe, and The Miami Herald. Contact him at Kyle.Toppazzini@TLeeCorp.com or tel. (613) 680–4333, ext. 2.


Horse is completely flogged

Hi guys. This horse done been flogged. Let's move on to other fun topics. Dirk QD

Very interesting discussion

I have long felt as most of you do. I started my career in Quality when the consulting world hadn't yet split into specialist camps they called "Six Sigma" and "Lean." At that point in time, if people were doing anything programmatic, they were calling it something like Total Quality. People studied the seven tools, and the seven new tools, and the Toyota production system, and SPC. We studied general systems theory, and learned to do process research.

When I joined Process Management International, they were, philosophically, a Deming and Juran organization with strong ties to the Japanese Union of Scientists and Engineers. They had sponsored US Seminars with Kano, Taguchi, Ohno and other Japanese Quality experts. In 2000, JUSE sent several people to study Six Sigma. They did an exhaustive study of the literature--such as it was at the time--and concluded that Six Sigma brought nothing new to the table in terms of tools or techniques, but it was useful as a "vehicle" or a way to bring Quality to an organization, and useful as part of a portfolio of programs that could help. The conclusion was that Six Sigma's role was for breakthrough. This pre-supposes an operational definition that positioins Six Sigma as a project-based methodology for improvement; essentially, a problem-solving paradigm.

What this has always meant to me is that you most effectively use Six Sigma and the full DMAIC or DMADV project life-cycles when you have problems with common cause variation, i.e., if your process is in control but you need to move the mean on target and/or reduce variation to meet some specification that's not currently met. It should be part of an arsenal that includes all the basic tools, the new tools, lean concepts, SPC, systems thinking, Theory of Constraints, diffusion of innovation, change management and anything else that can help manage systems and processes and provide for continual improvement.

My own observation is that the opinions I most often see from people in forums like this about Lean and Six Sigma have a basis in what they were taught, and who taught them. What I have seen over the past 20 years was a rift that was driven by consulting groups, some of whom were very good and taught a more systems-based, total-quality-based approach; some of whom, however, saw some narrow subset of tools when they were hatched, and built their whole consulting practice around that narrow definition. Since just about any quality approach will have dramatic effects on the low-hanging fruit, their inital experiences--even using their narrow approach--were successful, and all to often they "learned" that their approach was all any company needs.

What really matters, though, is not the name...that's just marketing. We have to be able to effect change in systems, to instill knowledge in leadership, to appreciate and understand that our systems comprise value streams, that to channel these requires an understanding of flow through the system and a constant pursuit of "on target and continually reducing variation." So do we need Lean? Absolutely. Do we need Six Sigma DMAIC and DMADV projects? At least for the forseeable future, I think they will be very useful in achieving breakthrough...in "Lean Transformation," Bruce Henderson included "Six Sigma levels of Quality" as one of the necessary things to have in place for full Lean implementation. Do we need SPC? If you don't have it, any Lean or Six Sigma approach are going to be hollow and temporary. SPC is often neglected, though...even the ASQ Six Sigma BOK treats it as an afterthought--you do it in CONTROL.

My own view is that we'll do much better as Quality Professionals when we stop the infighting about what we call things and start rendering unto Lean those things that are Lean and unto Six Sigma those things that are Six Sigma's. Learn systems theory, statistical theory (at least, as it applies to analytic studies), psychology and sociology as they apply to organizational change and what Rogers called Diffusion of Innovation; and pick up a useful iterative learning model to guide the approach and drive organizational learning and change. Learn which things are important to measure to actually drive improvement, then work to get things on target and constantly and forever reduce variation. Channel the value streams, optimize flow through those streams, and optimize the system.

And don't leave out eggs, either

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.


Thanks Karen I can appreciate your decisive answer however you are in many respects not correct.

1)The first point yes I would not disagree with this. I am quite glad you raise this point of novice conducting rapid Kaizen events that are not tied to an enterprise view. Government workers in Canada are being sold the novice approach and the intent of my article was to raise awareness.

2) Your second point is mathematically impossible given the tool set that Lean has to work with, i.e. that Lean can be used to estimate the impact of a root cause.  In order to establish truly if a root cause can predict a dependent variable you must use a concept called Granger Causality. Granger Causality relies on fairly advanced statistical testing to determine if Granger causality relationship exists. If the root cause is correlated with another variable then it maybe difficult to determine if it is the root cause or some other variable that is influencing the outcomes. In this case you would have to use Vector Auto regression techniques which are very advanced statistical methods. If the time series of the root cause data you are testing is non stationary you will also have to use other techniques to determine causality or transform the data to make it stationary. In any case lean and even six sigma do not have sophisticated enough tools to make such predictions and estimations of the effects of a root cause.  Six Sigma statistical tools (which are not really unique to Six Sigma) can be used to determine some cause and effect but not real causality.

3)The last point is also impossible to know unless you can test for stability. Lean does not have the statistical tests in its tool pack to test for stability.  

Finally I believe it is a liability to hold onto one and only one belief. In order for Lean, Six Sigma, TOC etc to evolve and progress we need to challenge the basic assumptions and recognize the limitations and benefits in each discipline.  I am very much a proponent for Lean and believe in its benefits however I recognize that other frameworks have their advantages as well.

Kyle - Thank you for sharing

Kyle - Thank you for sharing your thoughts. But I don't know where you're getting you definition of a fixed Lean "toolbox." Have you worked at Toyota? Statistical analysis, when needed, is a foundational apect of ANY improvement methodology. - Karen


Karen's argument is "mathematically impossible?" You decidedly do NOT need all thecomplexity you describe to determine and prove a root cause through a structured PDSA / Lean problem solving process. 

Stability in a system can be observed without mathematical proof. There's no need to overcomplicate everything with Six Sigma.


Hi Mark yes I realize what I described might be too sophisticated for you and this is why you have defaulted to your last statement . By the way what I described to Karen is not Six Sigma it is Econometrics.  I do not advocate a single disclipline but make use of the one that best fits the requirement. 

I think RIP gets it  

Read what I said

You are responding to something I didn't say. 

I said let's not overcomplicate things with Six Sigma. I didn't describe what you typed above as Six Sigma.

I could have also added "let's not overcomplicate things in general."


Thanks Mark I figured you would comment on my article and of course you tweeted it as you like to do. 

It seems to me you have taken a single and isolated point to distort the essence of the article. Even you yourself have written that six sigma techniques are utilized in conjunction with lean in health care. I think it is important to keep an "open mind" to these disciplines otherwise progress and innovation will come to a grinding halt.

None the less to address your point the 1 example I used about a hospital (which was not the premise of my argument) I actually have observed in a hospital in repeated cases. The hospital did undertake Lean. Maybe they should have hired you.

I think in terms of your first question you have asked me before and the number years I have been using lean has not changed, that is over 10. I also find it interesting that in some commentary you are quick to point out that Toyota has had recalls but in others you choose to say a comment like below. Appears that you flip flop on the issue. Anyways hope all is well with you

My last comment

Kyle -

I wasn't trying to distort anything or comment on the entirety of your piece. I only had time to comment on one aspect and that was your strawman. What you were describing sounds like "L.A.M.E." not true Lean. An equivalent would be somebody criticizing Six Sigma because a company spent a fortune certifying belts and then did nothing but cost cutting projects that led to a bunch of layoffs. That would also be a ridiculous straw man argument.

I'm not flip flopping. Lean and Six Sigma *can* be used together. But I disagree with your thesis that they MUST be used together. Toyota is not a perfect company. They have recalls. So do all the other automakers. Toyota uses the 7 basic QC statistical tools... you are welcome to try to convince them they should do full blown Six Sigma.



Thanks Mark I encourage people to go to Mark's twitter site and read his tweets. You will find some common patterns.

Karen is one of Mark's fans.  

Fan? Don't be a jerk.

If you're being insulting to me (as you were above), I would generally leave it alone (I understand multiple regression analysis, by the way).

But, to call Karen a "fan" of mine is disrespectful to her. She is a trusted and respected colleague of mine. She is an accomplished consultant and published author. To diminish her view by calling her a "fan" (as if that would make her views any less valid or correct) says a lot about your character, Kyle.

I am very disappointed that Quality Digest is giving you this platform.


You are correct yes Karen is your esteemed colleague. My apologies to Karen. I respect her view and I respect yours Mark.

Don't create a straw man argument


I'm not sure how much experience you have with Lean, but the emergency department scenario you created (reducing waiting room time while pushing that wait to the "to doc" time) is a pretty poor example of the Lean methodology.

In Lean, we look at the value stream... that's a pretty holistic view of a problem that leads to root cause solutions that don't push waste upstream/downstream or don't cause suboptimization.

I won't begrudge you for advocating for Six Sigma, but don't use a silly example of so-called Lean to make your case for what gap Six Sigma would be filling. 

By the way, Toyota has been quite successful using Lean without Six Sigma, as are many healthcare organizations.