How Archery can Help you get Taguchi’s Point

A few days ago, in conversation with Vicki Hall (the Institute’s most recently elected fellow), the subject of quality came up. Vicki’s a Business School professor and she was looking for some way to use a game to teach people about how to manage and improve quality.

In the course conversation, Taguchi’s loss function was mentioned. Taguchi was one of the many Japanese who had the opportunity to learn from W. Edwards Deming and Walter A. Shewhart (names worth googling if you don’t know them) after the Second World War, and his thinking contributed to the birth of “continual improvement”, or kaizen, among other things.

Taguchi held that quality decreases as variation from the target specification increases. In other words, “loss in value” increases as variation increases.

If you think of archery, when you hit the bull’s-eye your quality is “as required” and there is no loss …but the more you miss the bull’s-eye by, the greater your loss even if you are still hitting the target (are within “tolerance”) and not missing it altogether.

Taguchi Loss Function

As it’s a useful way to explain the thinking behind the Taguchi Loss Function (the name of which is enough to scare people) so I thought it would be good to share it.

Does experience help?

Common sense would seem to dictate that people with experience – those who have worked with a process – will get better results than those who are new to the job.

The old adage “practice makes perfect” reflects this and concepts such as on the job training are built on it. But is it correct? Deming’s answer to the question was a blunt “no” …before he qualified it with: “not if we are doing the wrong things”.

The common sense nature of his reply is such that some may discount it as being of little value. However, the challenge is in realizing when you are doing the wrong things – and Deming was challenging people to think.

Since at least the 1800s, people had jumped the high jump using variations of a forward jump. Then in the 60s an American, Dick Fosbury, decided to throw himself headfirst and backwards over the bar!

high-jump

The media thought it was a “lazy jump” but he won an Olympic Gold in the 1968 Olympics. Soon every high jumper realised they were doing the wrong thing and copied his innovation.

What periodic process review do you have in your organization to check if your processes are the right ones?