The Flaw of the 40–20 Rule in the Modern NBA

In the modern NBA, only 40% of conference finalists meet Phil Jackson’s famous threshold — down from 81% a decade ago. The decline reveals something bigger: championship contenders can no longer be identified by any single stat

What does it take to be a championship contender in the NBA? There’s a lot of ways to answer this question, and almost all of them would have some merit. Hall of Fame head coach Phil Jackson’s metric is a rather simple one. Known as the 40–20 rule, Jackson’s philosophy is that for a team to be seen as elite they must win 40 games in a season before they lose 20.

The rule is relatively sound mathematically, as it dictates that a team win two out of every three games consistently, which should measure out to a team that can win a championship. The thing is that for all the embracing of numbers and statistics, the 40–20 rule suggested that excellence could be measured systematically without accounting for the nuances of a season.

Jackson’s rule generally translates to teams that win the title — since 1999 only four teams didn’t meet the 40–20 threshold and still won a title. But if we consider conference finalists as “title contenders” then the reality shifts a bit, showing that trying to predictively measure what constitutes a contender is a flawed exercise to begin with.