Integrating or reconciling the PDCA framework from Lean and DMAIC from Six Sigma is the topic of this post.
Since both methodologies and frameworks share a common history, it is no surprise that integrating their respective frameworks was not difficult to do.
Below is my attempt at exactly that. Below the PDCA and DMAIC comparison chart, I’ll explain some big and some subtle differences.

Now, on to some differences between DMAIC and PDCA:
Differences Between PDCA and DMAIC
Visually, PDCA has 4 steps, while DMAIC has 5. But, it’s not just 5 steps, but 5 steps and tollgates in between each phase. A tollgate is where the project team or team leader presents his or her findings in the current phase and the steering committee will either approve the project to move to the next phase or not.
A big difference between PDCA and DMAIC is the corporate infrastructure required. Six Sigma and the DMAIC methodology in which its work is carried out, requires a steering committee, tollgates, a champion, and a project sponsor.
While all those might be good, given the right context, the organizational burden on a company is real because it requires up-front investment of time, resources, and attention.
On the other hand, the PDCA framework of Lean is completed many, many times without much hoopla or fanfare. Indeed, the PDCA framework of Lean allows for the involvement of everybody, whereas DMAIC of Six Sigma requires specialized and trained people, often called Black Belts, Green Belts, or Master Black Belts.
There are no belts in Lean; the mindset of Lean and the tools it uses to carry out its work is highly accessible to everybody – no belt required. No barriers to entry or barriers to participate, just some training, ongoing training, and a lot of hands-on doing.
So, in our compare and contrast of PDCA versus DMAIC, they are quite similar, except for the organizational infrastructure required in Six Sigma.
Because of the differences I note above, the benefits of Lean and the PDCA framework is often heralded because of its speed and velocity. This is true, because there is no organizational overhead and improvements are made – many, many small improvements – daily.
It’s Your Turn
Given the context and the company and the needs of the organization, consider the differences and the commonalities between Lean and Six Sigma. Where one might meet your needs, the other might not be right for you. You decide.
What do you think? Please share your opinion on the differences between Lean and Six Sigma.






{ 2 comments… read them below or add one }
Are you sure this is comparing the same thing?
PDCA in quality improvement programs is easily compared to DMAIC, however when considering PDCA in Lean, it is a slightly different matter.
When discussing PDCA in Lean, consider:
Lean for Manufacturing – moving parts and assembling
Lean for HealthCare – moving patients and equipment
Lean for Transactions – moving information
Is Lean being taken out of context? Lean on the production line, moving and assembling parts does not speak to Lean Manufacturings design and manufacturing quality (variation control), typically only the parts assembly is discussed. Also I am yet to see someone convincingly demonstrate Lean PDCA in non product/patient processes.
How does Lean really deal with hard to find quality problems which constrain flow? Why do organisations who apply both Lean and Six Sigma outperform those who apply Lean without any real consideration of quality first. Lean is only a component of the Toyota Production System, and in this context quality and variation has significantly more similarity to Six Sigma. John Shook on lean.org is always talking about yet another organisation claiming to be Lean, however beyond 5S and some kanban, it isn’t genuine Lean at all.
I also challenge the difference between western and eastern management and discipline. My observation is that Toyota has significantly greater discipline than most western organisations, and thus Six Sigma as a more disciplined tollgates methodology suits western culture, at least until we mature to a Toyota like culture. Is this why Lean Thinking has such high failure rates? Are western organisations, especially management simply not able to change quickly enough to make Lean work.
I am an advocate of Lean, however I am also practical. In my organisation, Lean is not working, not because it won’t work or it isn’t right for services, rather the senior management team don’t seem to get it. Lean Six Sigma has been working more effectively. I talk about an ideal future state where Six Sigma may be less visible and Lean pervades all work, however for now the skills, measurement/root-cause analysis, strategy, improvement selection, remuneration, customer focus, alignment, accountability, etc., etc. simply aren’t mature enough for Lean to be anything more than an initiative.
The above article states PDCA/Lean benefit is in its velocity, and I don’t agree. As a Lean Thinking and Six Sigma practitioner, I use each to solve different problems. I won’t use Six Sigma when it is not warranted, i.e. where the problem is hard to find variation which often can not be observed directly, a statistical approach is more useful and so I apply Six Sigma.
Interestingly enough my eight Lean Six Sigma Green Belts are leading 4 Lean oriented opportunities and 4 Six Sigma oriented opportunities, and not by design, just this was the opportunities at the time. Compare this to the corporate Lean only program where many Lean activities have been unsuccessful, trying to solve problems unsuited to Lean (not full TPS).
I think this is the real problem between Lean and Six Sigma. Toyota don’t do Lean Thinking, they have the much broader Toyota Production System which includes quality improvement and Just-In-Time (Lean), so yes Toyota have no need for Six Sigma. However for organisations who foolishly only cherry pick Lean only thinking and method without the broader TPS approach, Six Sigma makes sense. I think another difference between Toyota’s success and commonly poorly applied Lean Thinking (and Six Sigma) is that Toyota is far more than Lean or quality, Toyota have a real strategy management framework (Hoshin Kanri), providing clear focus, cascaded alignment, performance measures which guide decision making not judging employees, customer research/insight and focus, and a relatively simple business. When you compare many organisations to this standard, they simply don’t compare, they don’t poses the strategic and operational management to be a Lean Enterprise.
Black belts are program coordinators, PI mentors & coaches generally with deeper exertise and experience in problem solving, data analysis and tools.
Greenbelts are fundamentally trained SMEs
MBBs are trainers, Mentors, advisors.
These are all actions and players needed in successful Lean environments and most any other logical problem solving approach. Why the adversion to identify them as such in an easy to understand manner?
Associates, undergrad, grad degrees are similar mainstream guidence indicators.
Any growing, and improving business will need to invest in time, resources, (Scope) and attention. As in right sizing project teams to the scope of work & available time, So it is a businesses responsability to right size it’s infrastructural needs. Somee businesses do that well, some don’t. Tollgates are there to support teams and assure the business has a clear picture of the true opportunity especially in complex cross-functional type of applications. Those toll gates can be as formal as review committees or as informal as an individual using the same organized review internally as they solve day to day problems. Maybe if you see these things as limiting, perhaps your prior experience has been sub-optimized. We all have had that experience of thinking if that manager would just leave me alone, I could get this done a lot sooner or, if I could just do it my way with out all this red tape and questioning we could get on with it. Maybe some times that could be right but in complex shared environments that usually doesn’t work so well. Management, sharing, and coaching are cultural building blocks for businesses. Used well a business grows in knowlege and character and unity of vision. Used poorly…….? Well I think the operative word is Used WELL. I would suggest that above you are mistaking the uniform as the indicator of the teams ability to win the game.