Pareto Principle

Pareto principle
It was in 1941 that Juran discovered the work of Vilfredo Pareto. Juran expanded the Pareto principle applying it to quality issues (for example, 80% of a problem is caused by 20% of the causes). This is also known as "the vital few and the trivial many". In later years Juran has preferred "the vital few and the useful many" to signal that the remaining 80% of the causes should not be totally ignored.