Pareto Principle
About 80% of the results come from 20% of the work — so finding that 20% is most of the job.
Why PMs should care
Most features are barely used. Most revenue comes from a small group of customers. Most bugs live in a few specific parts of the code. Most support tickets come from the same handful of flows. This 80/20 shape shows up in almost every dataset a PM looks at, and if you ignore it, you end up spreading effort evenly across things that don't deserve the same attention.
The simple habit that helps: before opening any spreadsheet, stop and ask 'what's the 20% here?' You won't get the exact number right, but you'll get close — and you'll stop yourself from trying to improve everything at once.
Example in product work
A PM opens the feature-usage dashboard for a trading app expecting a surprise. Instead: the top 8 features out of 47 account for 84% of all sessions — watchlist, deposit, portfolio, search, buy, sell, price alert, statement. The other 39 — social feeds, educational modules, themed baskets, news feeds — split the remaining 16%.
The roadmap question changes from 'what should we improve?' to 'which of the top 8 is under-invested, and which of the bottom 39 can we sunset this quarter?' That's a three-hour meeting instead of a three-week discovery exercise.
What to do when you see it
- Most of your feature usage, revenue, bugs, and support tickets come from a small part of the product.
- Before opening a spreadsheet, ask 'what's the 20% here?' — it saves you from spreading effort evenly across things that don't deserve it.
- The split isn't always exactly 80/20. Don't wait for a perfect match before acting on it.
- Pareto helps you diagnose where to look, not how to rank. Ranking still belongs to RICE, Kano, and similar frameworks.
Sources & further reading
- Cours d'économie politique — Pareto, 1896The original work where Pareto observed that 20% of Italian landowners held 80% of the land — the foundation of the 80/20 rule.
- The 80/20 Principle — Richard KochThe definitive modern treatment of Pareto in business, management, and daily life.