The 80/20 Rule

Most stories about the 80/20 rule start with Vilfredo Pareto, a truly international guy. He was an Italian economist but he was born in France and he studied the distribution of wealth in England. The story goes that he first got interested in the phenomenon when he noticed that 20% of the pea pods in his garden produced 80% of the peas. He later looked at land ownership and noticed that 82% of Italian land was owned by 20% of the people. Then he discovered that 80% of the wealth in England was controlled by 20% of the population. Around 1906 he published some of his findings and the 80/20 rule was born.[i]

Other scholars took note such as Joseph Juran, a Romanian-born American engineer who was a pioneer in quality control on manufacturing lines in the 1940’s. He noted that 80% of problems are due to 20% of possible causes. He coined a phrase for this: “the vital few and the trivial many.” Specifically, he found that 80% of problems with products were caused by 20% of the production defects. By focusing on and reducing those 20% production defects, overall quality could be greatly increased at the least amount of expense. Juran became an important figure in Japan after lecturing there extensively on quality control issues. [ii]

In later years, Juran changed his now-famous expression to “the vital few and the useful many” to remind us that the other 20% of the problems and the other 80% of…