Last Updated on Friday, 18 December 2009 10:32 Written by Mark Chinery Saturday, 06 June 2009 19:12

Once upon a time, a pair of traveling tailors claimed to be able to make the finest magical clothing, invisible to all people unfit for their jobs.

There's no doubt that Six Sigma improves the quality and productivity, but is it the only way?

The tailors, after being commissioned by the emperor, only pretended to dress him, for no such fabulous cloth existed. When the newly clad emperor strode to the mirror to admire his fine new clothes, he was chagrined to see himself in only his underwear. However, he was afraid to say anything lest he reveal himself as incompetent, so he paraded through his kingdom and tried to ignore the autumn chill as best he could.

Everyone who saw him admired his fine new clothing, for they no more wished to reveal their shortcomings than he did. Those who could afford the costly garments followed his example and hurried to the same tailors for suits of their own. Soon, much of the kingdom was complaining about the unusually cold weather.

Companies are afraid not to adopt Six Sigma and spend tens of thousands of dollars on training because they don't want to be seen as quality improvement throwbacks, out of step with the new quality fads. To stay current with the trend, they specify Black Belt certification as a job requirement, thus excluding quality practitioners who can't afford the expensive Six Sigma wardrobe. But is the emperor's clothing wearing thin?

Unlike the emperor in the original fable, the Six Sigma emperor is wearing clothes, but has the designer label has cost several times its actual value? There's no doubt that Six Sigma improves quality and productivity, but is it the only way?

Motorola's original Six Sigma concept stressed the benefits of having six standard deviations between the nominal and each specification limit. "Less variation improves quality" is not exactly brain surgery. Henry Ford probably didn't know what a sigma was, but he attacked variation through advances in metrology (with Johannson, or Jo, blocks) and machine capability. Ford also introduced techniques now known as kaizen (continuous improvement), poka-yoke (error proofing), muda (waste) reduction, and just-in-time. Diligent use of the tools, not designer labels, yields the results. Interestingly, these latter techniques also incorporate, or are part of, key components of the 'lean' system - industry's current buzzword.

Mikel J. Harry and Richard Schroeder's book Six Sigma, The Breakthrough Management Strategy Revolutionizing The World's Top Corporation (Doubleday, 1999) differentiates Six Sigma from other quality programs by the declaration that "Six Sigma, unlike other quality initiatives, needs to be understood and integrated at every level of the organization if long-term companywide improvements are to be made." Unlike other quality initiatives? Armand V. Feigenbaum's book Total Quality Control (ASQ Quality Press, 1985) stresses that mere lip service from upper management is the "kiss of death" for any quality program. ISO 9000 cites management's role in the quality system and requires organizationwide awareness. Masaaki Imai's book Gemba Kaizen (McGraw-Hill, 1997) urges managers to spend time in gemba, the value-adding workplace.

Six Sigma identifies waste that includes inefficiencies and hidden plant waste. Waste suppression was paramount to Henry Ford's business strategy. And Imai adopts Ford's principles by calling for practitioners to attack all forms of waste.

The backbone of Six Sigma is the DMAIC (define, measure, analyze, improve and control) cycle, which sounds suspiciously like W. Edwards Deming's plan-do-check-act cycle: Identify a problem or opportunity, try to improve the situation, check or verify the results, and hold the gains. Repeat for continuous improvement.

Harry and Schroeder expand DMAIC to RDMAICSI: recognize, define, measure, analyze, improve, control, standardize and integrate. It works, but so does Ford Motor Co.'s TOPS-8D (Team Oriented Problem Solving, Eight Disciplines). DMAIC claims a data or qualitative focus. Tops-8D also can also use quantitative methods such as design of experiments and capability analysis.

The 8D system actually seems more versatile than RDMAICSI. It uses cross-functional teams, looks for root causes, and implements and tests permanent corrections or improvements. Six Sigma doesn't seem to add anything to it.

Six Sigma advocates may dismiss these statements as sour grapes from someone unwilling to pay the price to acquire a Six Sigma Black Belt: four weeks of training; a couple of workplace projects; and fees that may exceed the tuition for many night school masters' degrees in quality management, manufacturing-oriented business management, operations research and applied statistics. But basic engineering statistics, design of experiments, nonparametric methods, linear regression and statistical quality control are all separate college courses; one doesn't master this material in four weeks. No one who expects a magic bullet is going to find one--at any price.

There's no doubt that Six Sigma training equips the Black Belt to identify applications for designed experiments, work with cross-functional problem-solving teams and work effectively with a graduate of an applied statistics or quality management program. However, it's not a substitute for comprehensive mastery of the quality sciences.