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Six Sigma, Lean Tools, and Lean Sigma: Just a Bunch of Tools?

There are many “tools” approaches to organization improvement. One very popular program, which General Electric adopted with great success, is Six Sigma, an extension of Total Quality Management (TQM). Six Sigma refers to a goal of 3.4 defects per million units produced, and the focus is on training green belts, black belts, and master black belts. The training includes classroom sessions on the tools and a project purporting to save $100,000 or more. A presentation on the project is given to top executives as the last stage before earning the credential.

At the same time Six Sigma was spreading, companies were also selectively applying various lean tools in manufacturing and having some success with that. While Six Sigma focused on improving the value-adding processes—e.g., find the source of the quality problems or downtime on the machine center and put in countermeasures to fix it—lean focused on the whole value stream and creating flow among the value-adding operations. There is an obvious case for a harmonious marriage between Six Sigma, which fixes individual processes, and lean, which fixes the connections among processes.

Recently a new hybrid was born, Lean Sigma. I do not believe lean tools or Six Sigma tools or a marriage of the two will get a company to a lean learning enterprise. The following example from a company I worked closely with will clarify my concern about Six Sigma, lean tools, and Lean Sigma.

The CEO of a large automotive parts supplier wanted the Six Sigma program because of the great success of GE and Jack Welch. He worked with a group of senior managers and executives to pick the right consultants to do the training and determine how many certified Six Sigma black belts were needed. The leadership team reasoned that recent college graduates with high grade-point averages would be best suited to learn the complex statistical methods that are part of Six Sigma and decided to recruit bright young stars to become black belts. They recruited aggressively, offering a five-digit bonus and a brand-new car when they completed the Six Sigma program and achieved the required dollar savings. Needless to say, they attracted some topnotch young recruits.

Unfortunately, these young recruits had little if any manufacturing experience and stepped into these rust-belt factories with the mission to “fix processes” when these factories had been operating for decades with a well-established culture. Word got out about the hefty incentives for the recruits, which caused some managers and engineers to wonder why they should help these “youngsters” successfully complete a project when there wasn’t any payoff for them. The employees with an affinity for lean claimed that the projects being turned in as Six Sigma projects were actually lean projects—cells, pull, etc.

In my view, by treating lean and Six Sigma as two tool kits and then setting up a situation in which different groups in the company go to war over whose tool kit is bigger and better, the company created a self-defeating improvement program. In this particular case, there was enough dissent over the large incentives for the Six Sigma recruits, as well as the awareness that experienced employees were actually helping them, that management ended up not giving out any of the cars.

In the end, the company turned current employees into additional black belts. There still remained an uneasy tension between lean and Six Sigma, especially with internal lean zealots who viewed Six Sigma merely as tool kits. And the plant managers wondered what to do with the young black belts when they needed to move them into operational jobs, as their salaries were too high for the lower-level positions they were really suited for based on experience.

This is not to say the company should throw out Six Sigma or lean tools. Both are extremely powerful tool kits, but in the end, they are just tools. What companies need to be told over and over is that lean tools represent only one aspect of the broader philosophy of the Toyota Way. It seems like this is the most difficult lesson to get across to companies that want to “go lean.” Contrasts the myth of TPS as a set of tools to make short-term improvements on the shop floor with true TPS as the basis of a total management philosophy, based on a presentation by a Toyota manager (Glenn Uminger).

In reality, the training of internal Six Sigma and lean “experts” serves to reinforce the superficial tool orientation in the vast majority of companies. We will see in the Why Changing Culture Is So Difficult how Toyota has mentored international associates over five to 10 years to bring them to a deep understanding of the Toyota Way. Even Convis says it took 10 years of living in Toyota for him to begin to understand and he is still learning every day. Yet companies seeking to benefit from TPS and Six Sigma typically train employees for one to two weeks, ask them to do a project, and anoint them as experts.

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