The Pareto principle — 20% produces 80%

What the principle says

It is named after the economist Pareto, who noticed 20% of people owned 80% of the land. The point is not the numbers but the imbalance. Most revenue comes from a few customers, most bugs from a little code, most results from a few tasks. Causes do not produce effects evenly — that is the whole principle.

Where it holds and where it fails

It fits places that skew naturally: customers and revenue, stock and sales, complaints and causes. It fails where every item carries similar weight — an assembly where a single missing part stops everything. Before applying it, ask whether this is a skewed structure at all.

Using it in practice

It is most useful when deciding what to do less of, not more. List last month's work and mark what actually moved results; a few items produced most of the outcome. The rest are candidates to cut, automate or hand off.

• Find the few tasks that produced the results
• Fix the few causes behind recurring problems first
• Give your time to the core customers or income sources

Common misuse

Finding the 20% that produces 80% does not license discarding the rest — the core often runs only because the rest exists. 'Just do the 20%' also becomes an excuse to neglect basics. The principle is a tool for setting priorities, not permission to skip work.