In 1896, Vilfredo Pareto notices that roughly 80% of the land in Italy was owned by 20% of the people. Others began noticing this “Pareto principle” or “80/20 rule” show up in other areas, that a small number of inputs (the 20%) has a disproportionately large output.
In business, generally, 80% of the sales come from 20% of the customers — and 80% of the problems come from 20% of the customers.
80% of the road traffic is on 20% of the roads. 80% of the programming bugs are found in 20% of the code. Even if it’s not perfectly 80% and 20%, the general principle still applies: a small number of inputs lead to the majority of the outputs.Read more on themighty.com