Genichi Taguchi, 1924-2012


  • Author: Julian Champkin, Significance editor
  • Date: 24 July 2012

Strangely unmarked in newspapers and media has been the death last month of Genichi Taguchi. Of whom? If you have not heard of him, you have felt the effects of what he did. He was the statistician and engineer who revolutionised quality control in industry.

thumbnail image: Genichi Taguchi, 1924-2012

And if that doesn’t sound as though it is something that has touched you, you are wrong. If you have ever bought a car or a piece of electronics, or almost anything else that is manufactured, and if it bore the label ‘Made in Japan’, then the reason you bought it was because, throughout the1970s and ‘80s and much of the ‘90s, Japanese consumer products were better made and more reliable and cheaper to buy than almost anything made by European or American companies; and the reason for that is that Japanese manufacturers listened to Genichi Taguchi.

From the 1950s onwards Taguchi developed methods for applying statistics to improve the quality of manufactured goods. His key vision was that excessive variation in components lay at the root of poor quality of manufactured goods. He was not the first to see this; an American statistician by the name of W. Edwards Deming thought up the basic idea. Deming was unappreciated in America, but in 1947 he was asked by Japanese engineers, trying to restart manufacturing after the Second World War, to advise them. Taguchi was his pupil and disciple. He enabled them to take over the world.

All manufactured parts have variation in them; the length of a piston-rod, the resistance of an armature coil wire will vary, even between parts made on the same machine. Standard practice was to throw out any components that were oversize or undersize or outside the tolerances. Taguchi realised that that was wasteful and the wrong way round. Much better, he reasoned, not to produce the duff parts in the first place, and to minimise the effects of their variability. That, in a nutshell, was his contribution. It sounds stunningly obvious. It is what let Japanese manufacturing come from nothing in the 1970s and 80s to leave Europe and America struggling miles behind.

He was among the first to realise that the true cost of shoddy goods is not just the cost of those thrown-out parts, and is not just borne by the factory; it is actually paid by the consumer who buys the shoddy goods, in time wasted and profit lost while his car or whatever is not working, in time and money spent repairing it, in replacement costs when it wears out too early, and in irritation and aggravation and anger. And of course that consumer will learn, and will not happily buy your product again. But pioneer motorists in the 1970s who were persuaded to risk buying a Japanese car almost always bought another one the second time round.

British mass car making of the 1960s and 70s was a byword for low quality. Put crudely, the doors did not fit and the handles fell off. Thus was not only due to a demoralised workforce. It was due to bad design and manufacture, which led to customer dissatisfaction, to low sales, to low profits, and so to reduced ability to invest in either design or manufacture and a still more disgruntled workforce. When Japanese cars first went on sale in Britain they were derided; but their doors did not fall off. Within a decade they were the market leaders, with UK factories trying and failing to achieve their basic quality and reliability. The story in American was similar.

This again was due to Taguchi. He taught that one should minimise the effect on the final product of variations in its components. Minimise that effect of variation by designing the part properly, as well as by manufacturing it properly; and measure it properly as it goes along the production line so that you can throw it out at as early a stage as possible, rather than wait till you have to dismantle the whole car or subcomponent or whatever because of it. If your design is right, then only a few dimensions of a few parts will be critical – the product will still work just as well if other dimensions of other parts are a trifle less accurate. It is called Robust Design – or, just as often, the Taguchi method.

It profoundly affected costs of manufacture – it made things cheaper to make; it profoundly affected quality of manufacture – it made customers like them more. So it profoundly affected the profitability of the companies making them.

Which is why, although you may not have heard of Taguchi, you certainly have heard of two of the first followers of his lectures. One was a failing car company facing imminent bankruptcy; it was Toyota. The other was Akio Morita, the founder of Sony. It took western manufacturers twenty years or more to catch up with the Japanese. They began doing so in the 1980s when Taguchi volunteered to spend time at Bell Labs in America out of gratitude for American help to Japan after World War II. Since then he has been honoured worldwide.

Genichi Taguchi died in Tokyo in June this year at the age of 88.

This article first appeared on the Significance website. Visit the website for more web exclusive articles, book reviews, education pieces and videos, updated daily.

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