Named for Italian polymath Vilfredo Pareto, who noticed that 80% of Italy’s land was owned by about 20% of its population, the Pareto Principle states that a small amount of some phenomenon causes a disproportionately large effect. The Pareto Principle is an example of a power-law type of statistical distribution – as distinguished from a traditional bell curve – and is demonstrated in various phenomena ranging from wealth to city populations to important human habits.

The Pareto or 80/20 principle is a type of power law which states that roughly 20% of a set of causes result in 80% of the effects. ​The numbers don’t have to be exactly 80/20 though, and they don’t have to add up to 100%: both ’25/95′ and ‘5/70’ are also valid. The key idea is that in most cases cause and effect are not linear: a small subset of causes usual generate most of the effects.​

In any given scenario, if you can figure out the primary drivers for an effect you are seeing then you can better optimize the results.

  • Some examples: If you know that 20% of your customers are generating 80% of your revenue, you can find and focus on those 20% to provide better (or more) services. Conversely, you may be able to stop spending as much time on the other 80%.
  • If you know that 20% of your customers are generating 80% of your revenue, you can find and focus on those 20% to provide better (or more) services. Conversely, you may be able to stop spending as much time on the other 80%.
  • Let’s say 5% of customers generate 80% of support calls. With this you could try to figure out why they are struggling and provide additional documentation on your product up front or better set expectations before the sale.
  • Or if it turns out they are the type of customer you would rather not have then you can just ‘fire’ them and focus on the other 95% of customers that aren’t nearly as much work.  Many business have found by that ‘firing’ the 5% of customers that cause the most problems they lose little to no revenue and end up better off in the long run.
  • In the typical job there are only a handful of tasks or projects that provide the most value to your boss or organization. By finding them and then focusing on doing them well, you have a better chance at visibility, raises, and promotions.
  •  In school the same can be said of coursework. Most courses require an average amount of effort … and then there is the occasional course that requires more work than all the other courses combined for that semester (or even year)