Two, Four, Six, Eight ... Wait, No, Just Six.
Toyota got its own lean term. Anyone else? Motorola raised its hand in that great classroom known as industry and introduced ... Six Sigma.
While the methodology is lean at heart, its objective is more data-driven and statistically based. Six Sigma strives to reduce product- and service-quality problems or defects, which naturally translates into some lean-championed benefits like improved productivity, waste reduction, and enhanced customer satisfaction.
Six Sigma, so named because of its emphasis on the statistics measure of deviation from the mean, has fallen under fire lately with analysts questioning its validity.
A quick rundown of Six Sigma, according to Plant Services' asset manager: For normal distributions, 68% of the population should fall within one standard deviation, or sigma, of the mean. For quite some time, many companies upheld a three-sigma benchmark for quality, meaning that you could expect parts to be within specification 99.73% of the time (or have a defect rate of about 2.7 per 1,000 parts). However, Motorola noticed that a process could vary by nearly 1.5 sigma over time, which would mean those parts could have a defect rate of about 0.995 to 1.005 per 1,000. This slight variation in numbers could have a significant impact. For a 1.5-sigma drift in the mean, the sigma level would have to shift to a tolerance of plus/minus six sigma. This new acceptable tolerance level is 3.4 defects per million opportunities, or rather, at least 99.9996599% of data points should fall within plus/minus six sigma from the mean.
Got that?
Team Motorola figured that the ever-ebbing wave of technology was so complex that a more forward-thinking approach to quality levels was needed. Motorola Corp. was one of the first, back in the late 80s, to alter the notion that quality levels ought to be measured in parts per hundred to a case where quality levels should be measured in parts per million or parts per billion.
Since then, Motorola has reported savings of upwards of $17 billion. Not too shabby. The likes of Honeywell, 3M, and General Electric have followed suit, incorporating Six Sigma methodology into their lean practices.
So if money is being saved, mathematical minds are hard at work, and companies are going lean, what's the big problem? Plenty, according to analysts, starting with creativity.
A number of business publications have explored the criticisms of Six Sigma, coming to the same conclusions. First, the rigid and narrow standards of Six Sigma can stifle creativity, prompting "incremental innovation at the expense of blue-sky work." In other words, a company can get so caught up in meeting Six Sigma's limited acceptability that commitment to innovation or value is sacrificed in the name of stark quality. Second, that although the gist of Six Sigma is effective at fixing an existing process, it doesn't help in "coming up with new products or technologies," according to Business Week. Finally, some critics peg the standard deviation shift as arbitrary, maintaining the reasons for choosing six as the number is neither clearly defined nor justified.
What does this all mean? The lesson we have been learning all along: No lean process, be it TPM or Six Sigma -- worker based or data driven -- is a panacea for any business. What these methodologies ought to be promoting is a new way to examine processes, an example of how to think and act differently, and a basic outline for how to proceed successfully and effectively.
While the methodology is lean at heart, its objective is more data-driven and statistically based. Six Sigma strives to reduce product- and service-quality problems or defects, which naturally translates into some lean-championed benefits like improved productivity, waste reduction, and enhanced customer satisfaction.
Six Sigma, so named because of its emphasis on the statistics measure of deviation from the mean, has fallen under fire lately with analysts questioning its validity.
A quick rundown of Six Sigma, according to Plant Services' asset manager: For normal distributions, 68% of the population should fall within one standard deviation, or sigma, of the mean. For quite some time, many companies upheld a three-sigma benchmark for quality, meaning that you could expect parts to be within specification 99.73% of the time (or have a defect rate of about 2.7 per 1,000 parts). However, Motorola noticed that a process could vary by nearly 1.5 sigma over time, which would mean those parts could have a defect rate of about 0.995 to 1.005 per 1,000. This slight variation in numbers could have a significant impact. For a 1.5-sigma drift in the mean, the sigma level would have to shift to a tolerance of plus/minus six sigma. This new acceptable tolerance level is 3.4 defects per million opportunities, or rather, at least 99.9996599% of data points should fall within plus/minus six sigma from the mean.
Got that?
Team Motorola figured that the ever-ebbing wave of technology was so complex that a more forward-thinking approach to quality levels was needed. Motorola Corp. was one of the first, back in the late 80s, to alter the notion that quality levels ought to be measured in parts per hundred to a case where quality levels should be measured in parts per million or parts per billion.
Since then, Motorola has reported savings of upwards of $17 billion. Not too shabby. The likes of Honeywell, 3M, and General Electric have followed suit, incorporating Six Sigma methodology into their lean practices.
So if money is being saved, mathematical minds are hard at work, and companies are going lean, what's the big problem? Plenty, according to analysts, starting with creativity.
A number of business publications have explored the criticisms of Six Sigma, coming to the same conclusions. First, the rigid and narrow standards of Six Sigma can stifle creativity, prompting "incremental innovation at the expense of blue-sky work." In other words, a company can get so caught up in meeting Six Sigma's limited acceptability that commitment to innovation or value is sacrificed in the name of stark quality. Second, that although the gist of Six Sigma is effective at fixing an existing process, it doesn't help in "coming up with new products or technologies," according to Business Week. Finally, some critics peg the standard deviation shift as arbitrary, maintaining the reasons for choosing six as the number is neither clearly defined nor justified.
What does this all mean? The lesson we have been learning all along: No lean process, be it TPM or Six Sigma -- worker based or data driven -- is a panacea for any business. What these methodologies ought to be promoting is a new way to examine processes, an example of how to think and act differently, and a basic outline for how to proceed successfully and effectively.
posted by A King at
7:10 AM
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