What is Quality - Taguchi Genichi

1. Taguchi Genichi

Taguchi Genichi 田口 玄一 was a Japanese
engineer and statistician. Taguchi was raised in the
textile town of Tokamachi, in Niigata prefecture. He
initially studied textile engineering at Kiryu
Technical College with the intention of entering the
family kimono business. However, during World
War II, he was drafted into the Astronomical
Department of the Navigation Institute of the
Imperial Japanese Navy. After the war, in 1948 he
joined the Ministry of Public Health and Welfare.

2. 
From the 1950s and onwards, Taguchi developed a
methodology for applying statistics to improve the
quality of manufactured goods. As a result of his
success, he eventually became well-known in both
Japan and the United States, with companies such as
Toyota, Ford, Boeing and Xerox adopting his methods.

Taguchi has made a very influential contribution to
industrial statistics: one of them being the Taguchi
loss function which is used to measure financial loss
to society resulting from poor quality.

3. 
Taguchi suggests that every process has a target value
and as the product moves away from target value,
there’s a loss incurred by society. Taguchi calls
common cause variation, as the noise. The attempt
should be to meet the target value, rather than being
within upper, and lower specification. As you move
away from the target value the loss increases. He also
stated that the smaller the variation around the target,
the better the quality.

4. 
Based on this he proposed the following: as
conformance values move away from the target, loss
increases as a quadratic function. This loss is
proportional to the square of the distance from the
target value. Taguchi’s approach is not to eliminate or
ignore the noise factors, but aim to reduce the effect
or impact of the noise on the product quality.