How much does the top fifth hold?
The top-share rule depends on a distribution; it is not always exactly 80/20.
Inside this model
For a Pareto distribution with exponent α=shape/10>1, the top q share is q^(1−1/α). The plot shows the share owned by the top 1–50%.
Out in the world
A practical use
Compare whether a few products account for most sales in an uneven portfolio.
A useful lens. Not a universal law.
- This is one stylized distribution; a measured top share does not prove the underlying mechanism.
Associated thinkers
Further reading
Explore the original research or the teaching reference behind this experiment.
Vilfredo Pareto — Cours d'économie politique ↗