My whole career, I have worked with the Lean methodology (aka the Toyota Production System). I've just really never done much with Six Sigma. I've read about Six Sigma and I took a Green Belt course when I worked at Dell in the late 90s. I've studied and used statistical methods (especially what I learned in my Industrial Engineering studies and at MIT), but I've never done anything I would call Six Sigma in my career.
I have respect for Six Sigma as a discipline, just as if I were a chef, I would have respect for pastry chefs. They can co-exist in the kitchen and you might both use whisks, but you have slightly different training to do different things – these roles aren't interchangeable and neither are Lean and Six Sigma. That's one reason I get riled up about so-called “Lean Sigma” or “Lean Six Sigma.”
Most of the “L.A.M.E.” (Lean As Mistakenly Explained) that I see on the interwebs comes from “Lean Sigma” discussions, especially on LinkedIn.
What are the fallacies that are thrown around? They include, but are not limited to:
- Lean is about the average, Six Sigma is about the variation
- Lean is about internal processes, Six Sigma is customer focused
- Lean is for efficiency, you need Six Sigma for quality (this one is the fault of Mike George and his books, many say)
- Lean and Six Sigma are just toolboxes and you use whichever is appropriate for the problem at hand
These are all incorrect, as somebody with good Lean training or Lean experience would realize.
Lean focuses on the average AND variation
I've used Lean in settings like hospital laboratories where the focus was on both the average testing turnaround time and reducing the variation. This was done by improving flow, reducing batching, improving the standardized work (and having a kaizen, or continuous improvement, process in place). I'm sorry, we didn't “need” Six Sigma to focus on variation.
A related fallacy is to say “Lean doesn't use statistics.” Toyota doesn't practice Six Sigma in any formal way, but they use the “7 basic QC tools,” as do many Lean people (including histograms, etc.).
Lean is inherently customer focused
In this hospital lab testing improvement work, we talked with doctors and nurses (“internal customers”) and patients and their families to figure out which lab tests were the highest priority for fast and accurate medical decision making and what patients thought about being woken up at certain times of the morning to have their specimens collected. Lean hospitals often include a patient or two in “Rapid Improvement Events” (something that should be done more often, actually).
It's not hard to find stories in the Toyota literature (including Jeff Liker's books) about that company's deep respect for the customer and the deep understanding of the customer's needs, from a product design and manufacturing standpoint (although, reportedly, the Toyota dealers in the U.S. still have a long way to go).
Lean is about flow AND quality
The two pillars of the Toyota Production System are “just in time” (improving flow) and “jidoka” (quality at the source) – see the diagram of the “TPS house” here. There is a “lean six sigma” healthcare book that says explicitly (and completely incorrectly) that Lean addresses every type of waste except for the “waste of defects” and that you need Six Sigma to address that. Malarky! Lean (going back to the roots with Toyota and Dr. Deming) is inherently a quality improvement system. Quality and flow go hand in hand. That's a lesson I learned well when I worked at GM under our plant manager who had been one of the first GM leaders to work at the famed NUMMI plant (Larry Spiegel, he was quoted in this radio story).
Lean is NOT just a “toolbox”
Lean is a quality improvement system, a management system, and an organizational culture.
I read something the other day, again, about the “toolbox” thing. I've had many people tell me that their “lean sigma” training was almost entirely about Six Sigma and that they had a few hours of introduction to Lean tools, like 5S.
I don't blame the individuals who are spouting these fallacies about Lean being just a toolbox. They are only regurgitating that they have read or what they have been taught by some “certified lean six sigma master black belt” (or CSLMBB). They sadly don't have exposure to Lean as a management philosophy, as I did back to my early days at GM (again, thanks to people like Larry Spiegel, not the average old-school GM managers).
People are certainly free to do whatever they want. I just wish when they are only using a “Lean toolbox” (or just one tool) that they don't call it Lean.
Call it “5S Six Sigma.”
Call it “Lean Toolbox Six Sigma.”
Better yet, keep the name “Lean” out of it, please.
Final thought – lest I get accused of being “anti Six Sigma,” that's not the case. I'm opposed to misrepresentations of the Lean methodology. This kind of malarky hurts everybody who is trying to do things the right way. I'm opposed to “L.S.S.A.M.E.” This isn't a “fight between Lean and Six Sigma” — it's a fight between knowledge and ignorance.