Eighty20 is named after the Pareto Principle, also known as the 80:20 Rule, or The Law of The Vital Few. This rule was first observed by Vilfredo Pareto, an Italian economist who showed that in his country, 80% of the land was owned by 20% of the population. He saw the same in his garden, where 20% of the plants yielded 80% of the produce. And so, the 80:20 rule was born, which states that 20% of the input generates 80% of the output.

Source: one, two