Competitive balance is really bad in the NBA. It’s really bad. The best test for parity is the Noll-Scully (we have a full article on calculating it.) This test compares how the real NBA looks with an ideal NBA where everything was fair. The ideal value in the Noll-Scully is 1.0, the further away from 1.0 the less balanced a league is. The last several seasons the NBA has had a Noll-Scully of around 3.0. This means the league is three times more spread out than we’d expect it to be if everything were fair. With a schedule of 82 games, we’d expect most teams to be between 30 and 50 wins. Yet, in the real NBA teams routinely win close to 60 and some easily win fewer than 20 (during an 82 game season).
Looking over the NBA’s history we see the 90s hit the peak of unfairness, ending with the Jordan lead Bulls disbanding and a lockout giving us a shortened season. Over the 2000s the league was much more fair than the 90s before starting to creep up over the last several seasons. Then we see a similar thing has happened: the defending champs lost their best player and a lockout shortened the season. And maybe as a result of this the parity of the league has gotten a little better.
An interesting thing to note is that the league was at the height of its popularity during the Bulls three-peats with Michael Jordan, Scottie Pippen, Dennis Rodman and Horace Grant. Competitive balance does not seem to be the key indicator to the league’s popularity. In fact, over the last 20 years the NBA simply hasn’t been balanced and even at its best, it is still much less balanced the the NFL, NHL or MLB. The NBA’s competitive balance had been getting worse in recent years. It’s possible it is now going down to its 2.5 level, which is still wildly unbalanced. The question we should ask is if having a competitive league is something we should be rooting for, or if we should be rooting for good teams that many people want to watch.