The 80 20 rule states that 80% of results come from only 20% of work or effort. This rule has been observed by many researchers in various situations. Here are some examples to illustrate this rule:
- 80 percent of revenue of a company is made by only 20 percent of workers
- 80 percent of software bugs come from only 20 percent of the code
- only 20 percent of the population in a country enjoys 80 percent of its wealth
While not everyone would agree on the percentages, the important thing to learn from this rule is that most things in life are not distributed evenly. That is to say, the ratio is never 1 to 1. For 1 unit of input you will not get 1 unit of output.