The 80/20 rule states that 80% of effects are determined by 20% of their causes. The rule is also known as the Pareto Principle, after the 19th Century Italian economist, Vilfredo Pareto. Pareto noticed that 80% of the peas in his garden came from 20% of the peapods. (Weird thing to notice.) He also showed that about 80% of the land in Italy was owned by 20% of the population.
The Pareto Principle is not a law, like gravity. It’s a rule of thumb. It fits a wide array of phenomena. Consider, for instance, these applications of the rule across a variety of fields: (more…)