Pareto Principle / Pareto Chart
80/20 rule — few causes produce most of the effect. The Pareto chart visualises this with sorted bars and a cumulative curve.
Also known as: Pareto, Pareto principle, 80/20 rule, Pareto chart
The Pareto principle (Vilfredo Pareto, 1896) states: about 80 % of the effect comes from about 20 % of the causes. In Six Sigma this means: focus improvement work on the few vital few defect types / causes, not on the trivial many.
- Pareto chart — bars sorted descending by frequency, plus a cumulative percentage line
- Reading — which 2–3 bars already make up > 70–80 % of the total frequency?
- Data base — needs categorised counts (defect types, complaint reasons, incident causes)
- After improvement — draw the Pareto again; the ranking shifts (attack the new remaining "vital few")
See also
Used in
Sources
- Juran, J. M. — Juran's Quality Handbook, 5th Edition, McGraw-Hill, 1999
- Pyzdek, T. & Keller, P. — The Six Sigma Handbook, 5th Edition
- Ishikawa, K. — Guide to Quality Control, 2nd Edition, Asian Productivity Organization, 1982