Involves

Word

Pareto principle

puh-RAY-toh PRIN-suh-puhl · noun

The rule of thumb that roughly 80 percent of the results come from about 20 percent of the causes

Examples

  • Twenty percent of the codebase produced eighty percent of the bug reports: the Pareto principle, on schedule.

  • Applying the Pareto principle, she found the handful of clients generating most of the revenue and most of the complaints.

Origin

Named for Vilfredo Pareto, the Italian economist whose 1890s work found that a small fraction of the population held most of the wealth, in country after country. Quality pioneer Joseph Juran generalized the pattern to defects and management in the 1940s and attached Pareto's name to it.

How it connects

The name for the lopsidedness, borrowed from an economist who measured it first.

This word appeared in The vital few, the Involves connection for July 26, 2026, which asked: Why do a few causes produce most of the results?

Check yourself

What does the Pareto principle claim?

A small share of causes tends to account for most of the effect.. Right. The claim is imbalance, not the specific split. The 80/20 ratio is a memorable emblem, not a law of nature.

What the sources establish

  • Pareto's economic studies in the 1890s documented that income and wealth distributions were highly concentrated, following a regular mathematical pattern across countries.

  • Joseph Juran generalized the concentration pattern to quality management and coined the name “Pareto principle,” later admitting he could have called it his own.

Sources