The Pareto principle—more informally called the 80/20 rule—refers to the idea that 80 percent of outcomes come from 20 percent of causes. It originated with Vilfredo Pareto, an Italian economist who observed that 80 percent of the land in his native Italy was owned by just 20 percent of the population. When he later noticed that 80 percent of the peas in his garden came from just 20 percent of the pea pods, Pareto hypothesized that this was something of a “magic” distribution in nature. Put simply, the 80/20 rule says that a small number of inputs drive most of the outputs.
