The Question: If NBA teams were ranked like chess players, who would be the best team ever & where does everyone stand now?
The Short Answer: The 2016-17 Warriors are the best ever, & as of April 2025 the Celtics are on top.
Elo is the system chess uses to rank players. Every team starts at 1200, the winner of each game takes points from the loser, & beating a strong team is worth more than beating a weak one. I ran it over every game from November 26, 1946 to April 16, 2025, 71,794 games in all.
Elo History, 1946–2025
This graph shows the month-end Elo for all 30 franchises since 1946, with five dynasties highlighted. The key takeaway is how rarely a team stays on top for long. Every highlighted team has both climbed above 1800 & fallen below 1000 at some point. The highest point on the whole graph belongs to the Warriors at 2006 in June 2017.
Final Elo Ranking, April 2025
As of April 16, 2025, the Celtics lead the league at 1772, 118 points ahead of the Thunder at 1654. The Nuggets are third at 1547. 18 teams sit above the 1200 starting point & 12 sit below it. At the bottom are the Hornets at 763 & the Wizards at 750.
Greatest Team-Seasons by Peak Elo
This is the highest rating each team reached in a single season. I left off each team's first 10 games of a season so no one gets credit for last year's rating carrying over. The 2016-17 Warriors at 2006 are the only team-season to break 2000, followed by the 2017-18 Warriors at 1986 & the 1996-97 Bulls at 1956. Surprisingly, the 73 win Warriors of 2015-16 only come in 5th at 1909. Between them the Warriors & Bulls hold 8 of the top 15 spots.
Franchise Elo Range
This graph shows the all-time high & low for each franchise along with where they finished. The Warriors have the widest range, from 646 in March 2002 to 2006 in 2017. The Jazz have fallen the furthest from their peak, from 1843 in 1999 down to 902. One thing to keep in mind is that the data splits franchises by name, so the Thunder only start in 2008 & the Wizards in 1997. The Hornets also cover both the original Hornets & today's Charlotte team.
Elo Gap vs. Win Rate
Naturally, the question is whether any of this predicts anything. In the 71,696 games where the two teams had different ratings, the higher rated team won 61.9% of the time. When the gap is under 25 points it is a coin flip at 49.7%. When the gap is over 400 points, the higher rated team won 73.5% of the time.
2024-25 Season Race
Lastly, the 2024-25 season game by game for the six top rated teams. The Celtics stayed between 1719 & 1789 the entire year. The biggest climb was the Thunder, from 1390 at the start of preseason to 1654. The Cavaliers made a similar run from 1287 to a peak of 1541 in March. The data does include preseason games & stops on April 16, 2025, before the playoffs started.
Comments
I think the main takeaway is that Elo does a good job of finding dynasties. The teams one would expect, the Jordan Bulls, the Curry Warriors, the Bird Celtics & the Magic Johnson Lakers, all show up at the top. At the same time no rating lasts. The Spurs were at 1842 in 2017 & finished at 981. Going into the 2025 playoffs, Elo had the Celtics as the favorite with the Thunder closing fast.