laws & principles
Pareto principle
What is the Pareto principle?
The Pareto principle is the observation that most of the effect comes from a small part of the cause - roughly 80% of the value from 20% of the things. In product terms, a handful of features carry most of the use.
Also known as: 80/20 rule, Pareto's law
The demo
Ten features, sized by how much they're used. Click them to add up their share of all usage - and see how few you need to reach most of it. Try the biggest ones first.
Selected: 0% of all usage, from 0 of 10 features
Click features to total up their usage share.
What this demo shows (text version)
A bar chart of ten features whose usage is steeply uneven: the first two features account for about 80% of all use, and the remaining eight share the last 20% between them. Clicking a feature adds its share to a running total shown above the chart.
Selecting just the top two features reaches roughly 80% of all usage - a fifth of the features delivering four-fifths of the value. That is the Pareto principle, and the takeaway is to concentrate effort on the vital few that people use constantly, while remembering the long tail still matters to the people who depend on it.
You reached four-fifths of all usage by selecting just a couple of features out of ten. That lopsidedness is the Pareto principle, and it changes where you spend effort: the vital few deserve most of your craft, while the trivial many can wait - or go.
The number isn't magic - it's not always exactly 80/20, and you shouldn't force it. The useful move is to actually look at your usage data and find the real distribution, which is almost always lopsided. Polish the few things people do constantly before you perfect the ones they touch once a year.
Two cautions. The long tail still matters to someone - a rarely-used feature can be mission-critical for the person who needs it, so "20% of use" is not the same as "safe to delete". And don't let the vital few become an excuse to neglect accessibility or edge cases that decide whether people can use the product at all.