In a recent conversation I again found myself between two smart blokes, one who was a black belt 6 sigma consultant who believed the problems of the world could be fixed by some aggressive, numerical focus on process improvement, and an exponent of Lean, who was of the “build the right culture and they will come” school.
To my mind, they are both right, and both wrong.
Six sigma means defects of less than 3.5/million. This requires rigorous emphasis on elimination of anything that creates variation in a process, or series of processes, ensuring that the output is exactly the same every time. Good six sigma implementations take great care to ensure that the output of the processes that are so exactly the same are adding value to the customer, but this can become lost in the welter of statistics and process control mechanisms.
Lean, by contrast starts with the macro question of “what customer value does this process add? What would the consumer prepared to pay for it?” Anything that does not add value to the customer, inventory, rework, excessive movement, and others, is deemed to be “waste” and is rigorously targeted for improvement using the old “Plan, Do, Check, Act” process, the ultimate objective of which is “flow” through a process.
The tools of lean and 6 sigma are widely interchangeable. I have seen 6 sigma implementations going through a 5S process, essentially a lean tool, and Lean implementations using SPC extensively to identify and manage out waste in a process.
It can be said, as my conversationalists did, that 6 sigma is an analytical, quantitative tool box, and Lean is a Cultural, management alignment toolbox. They they are both right, and both have their place, indeed elements of both are essential to competitive improvement.
TQM, another 3 letter acronym!
For me, the key is the outcome, a better, more reliable, cheaper, product that meets my needs. From the manufacturers perspective it offers quality, reliability, and the opportunity to choose how to deal with the enhanced margin in competitive markets.
The route to that outcome is a management exercise that uses tools, 6 sigma, lean, TQM, different names, essentially interchangeable tools coming from 3 toolboxes, that are used to meet the needs of differing circumstances.
Toyota’s TPS evolved over 30 years, starting in post war Japan where the demand for cars was small and patchy, and not met by the gas guzzling monsters the Americans were producing, components hard to come by, and production lines very basic. Taiichi Ohno Toyota’s production manager at the time later recognised as crucial to the development of TPS set out to accomodate the shortcomings of the Toyota plant by introducing the disciplines that became TPS. The irony is he built on the work of Amercian gurus, significantly Henry Ford, and W. Edwards Deeming, whose work on improvement and flow had been forgotten after the war.
Always a great discussion as improvement is so dear to my heart.
People readily associate Toyota and its success with Lean (TPS) However the TPS is only a small componenet of a much bigger picture. And right at the heart of what Toyota do is TQM. People would argue the fact but Six Sigma and TQM are fundamentally the same.
Hence Toyota in effect is practicing both Six Sigma (TQM) and Lean and has stayed true to the methodology. While in the West we have a habit of rebadging methodologies and constantly searching for a silver bullet.
Totoyas success is built upon people involvement, standardised work, reliable processes and a robust investigation system when things do not go exactly according to plan.
The reality is if you have all your people on board you can make anything work. For me this is the starting and end point with the tools of TQM and Lean coming along for the ride and only when required