NBA Analysis: The Value of PER
Player Efficiency Rating (PER) is an all-in-one basketball rating created by former Memphis Grizzlies executive John Hollinger. The formula is complex but the image below shows the stats that get factored into calculating PER.
Throughout this article, I will examine how PER holds up as an insightful metric and if there have been any trends revealed.
Defense
Hollinger has acknowledged that PER is weighed more towards offensive input because rebounds and steals do not tell the full story. The perfect example is Draymond Green, he is an elite defender but the year he won DPOY his PER was only slightly above the average of 15 (16.51). This is part of a larger issue when it comes to quantifying defense, how do you reward a player for preventing an offensive attempt from even being considered? Another example is Tony Allen who was one of the best defenders in the league on the Grit and Grind Grizzlies but routinely posted a below-average PER. Rudy Gobert has the opposite issue (not technically an issue); he routinely posts 20+ PERs each season because of his scoring efficiency in the paint and his high number of blocks per game.
MVP
The MVP voting is flawed, I can go down a rabbit hole as to why media votes should not be a thing anymore. But an interesting trend noticed from the 2008–2009 season to the most recent season (2020–2021) is that 83% of MVPs also had the highest PER that season. The only two seasons where it was not the case were 2014–2015 when Steph Curry had the 3rd highest PER after Anthony Davis and Russell Westbrook, but the Pelicans that year were a team coming in as the 8th seed and OKC missed the playoffs that year with Kevin Durant injured. The other case was the 2010–2011 season when Derrick Rose was MVP while LeBron had the highest PER and Derrick Rose had the 9th best. This also can be explained by the impressive fact that Derrick Rose brought the Chicago Bulls from the 8th seed the previous year to the 1st seed. To continue the PER-MVP correlations from these season ranges :91.6% of MVPS were top 3 in regular-season PER. With the lone exception being the previously mentioned 2010–2011 season, however, Dwight Howard and LeBron were in the top 3 in both PER and MVP voting that season.
Championship Teams
When looking through trends between PER and championship teams I found out that 75% of championship teams had at least 3 players in the top 50 PER for the regular season, with the only criteria being having played at least half of the season. From the 2008–09 season to the 2020–2021 season 91.6% of championship teams had a player top 10 in regular-season PER. The only time it did not happen was the balanced 2013–2014 Spurs team that managed to have 5 players top 50 in PER and true to form is still remembered for their brand of team basketball where a different player could be the star on a given night.
Playoff Performance
PER can (emphasis on “can”) be used as an effective indicator of relative decrease or increase in performance. For example, during Dirk Nowitzki’s legendary championship run, his playoff PER was 25.33 compared to his regular-season PER of 23.52. In other words, he stepped up, while LeBron’s playoff PER of 23.78 compared to his regular-season PER of 27.34 that season can show that he underperformed. Another example is LeBron having a PER of 37.43 during his 2009 playoff run, while he did not have a single teammate in the top 50 for playoff PER. This implies that he stepped up offensively during that playoff run for Cleveland relative to his regular-season PER of 31.76 that season.
Conclusion
There is no way to fully capture the value a player brings but PER does a very good job on the offensive end. There will always be players like Draymond Green and Tony Allen that will not be done justice by general metrics. Another issue as well is team fit, and lineup fit in general. What is asked of a player can always change; when Scottie Pippen took over as the centerpiece of the Bulls’ offense when Jordan retired the first time, on paper it may look like a dramatic increase in scoring ability but it was actually an expansion of role. But overall, the MVP and postseason trends do leave me confident that PER does tell a story of player value, player impact, and team construction.
