Roger Hoerl, of GE Global Research, kicked off the conference with a presentation titled, “A fresh approach to integrating Lean and Six Sigma”. His presentation was quite “Lean” at only 12 slides, but the message was clear… The way Lean and Six Sigma have been integrated in the past is based on faulty assumptions and he suggests a better way.Below are the three faulty assumptions and their correct counterparts:
Faulty Assumption 1: There are “Lean tools” and “Six Sigma tools”
Correct Assumption: Neither Six Sigma nor Lean has “invented” tools – Therefore, there are no such things as Lean or Six Sigma tools: each can steal whatever tools it likes
Faulty Assumption 2: Six Sigma works for quality CTQs, but not for waste or cycle time
Correct Assumption: Roger said that half of his Six Sigma projects at GE focused on reducing waste or cycle time. Reducing waste and cycle time are CTQ’s
Faulty Assumption 3: Lean is an improvement methodology, comparable in nature to Six Sigma
Correct Assumption: Lean is not an improvement methodology. It is fundamentally a set of principles (as quoted my Michael George)
He then defined what Lean and Six Sigma truly are, stating that understanding how they are different is key to integrating them:

“Fundamentally, Lean is a documentation of the key attributes of the Toyota production system.”

“Fundamentally, Six Sigma is an improvement methodology (with a dynamic tool set).”
And finally the better way: Hoerl suggests that applying each initiative according to its strengths – “Six Sigma for its deployment methodology and infrastructure, and Lean for the universal validity of its timetested principles”, is the best way to integrate them.
You can bet the next time someone asks me how to use Six Sigma and Lean together, I’m going to refer them to Hoerl. He’s got more than the answer, he’s got vision.