Lately, there has been a great deal of talk around Lean execution for different industries, even starting a Lean certification program. Some speak of Lean, some of Six Sigma, and some, combination of Lean and Six Sigma.
While healthy discussions between experts are needed to always stimulate the mind and ideas of process improvement professionals, this 'pre-historic' question about which is better between Lean and Six Sigma has become overused to the point of it being irritating.
So which is better?
Here's my take. Lean focuses on speed, Six Sigma on eliminating defects and variations. Lean and Six Sigma are complement each other. They are a perfect match.
As a process improvement professional, even as a manager in general, you should have the two in your toolbox. IF your problem is about looooong processing time, use lean tools, techniques and methodology. IF your problem is about recurring defects or variation of outputs, use DMAIC and Six sigma tools.
IF your answer is ONLY lean, or IF your answer is ONLY Six Sigma, you have a BIG PROBLEM. If you are a consultant, your clients have a BIG problem that is YOU.
"...if all of you have is a hammer, everything looks like a nail" (Maslow, The Psychology of Science, 1966)