80/20 Rule

The 80/20 rule states that 80 percent of the effects of something come from 20 percent of the causes.

The 80/20 rule is also known as the Pareto Principle after the Italian economist, Vilfredo Pareto, who first mathematically analyzed the distribution of wealth in Italy.

The 80/20 rule helps prioritize improvement efforts. Working on the critical few causes, the 20%, can yield big gains.