Do you remember ESPN’s catch-all the metric, Real Plus Minus (RPM)? It vanished from their website, and before it did, ESPN had modified it. On Reddit, you can find fans who appreciated the original RPM, disliked the updated version, and wondered why it disappeared altogether.
The good news is that the creator of RPM, Jeremias Engelmann — who previously worked as an analyst for the Phoenix Suns and later the Dallas Mavericks, and now appears regularly on the German podcast “Jeden Tag NBA” — has brought the metric back. It’s called xRAPM, and it’s publicly available on his website. Spurs fans will find plenty to like about it.
Jeremias described his approach to xRAPM in a December 19, 2024 episode of “Jeden Tag NBA.” to host Jonathan Walker. The conversation is in German, but I’ll translate the crucial points as best I can. What follows isn’t their exact conversation — far from it, as their discussion lasted 90 minutes! The Spurs-related insights that follow weren’t part of their talk either; they’re my own observations based on Jeremias’ website, which I highly recommend checking out.
Why Is RPM Now Called xRAPM, and Why Did It Disappear?
RPM was originally called xRAPM. When Jeremias licensed it to ESPN, they renamed it RPM, reportedly because they disliked the “A” in xRAPM due to possible associations with unwanted terms. ESPN still owns the RPM name but removed it from their website when Jeremias joined the Mavericks. Now freelancing for Royce Webb’s Substack, Jeremias has revived the metric under its original name, xRAPM.
What Exactly Is xRAPM?
The name has three parts:
APM (Adjusted Plus Minus) was the foundation. This metric relies solely on lineup data, not individual stats, to calculate a player’s impact on their team. While the widely known on-off plusminus (available on bk-ref) describes the difference between team points scored and team points allowed while a specific player is on the court (a “rough” calculation, according to Jeremias), APM is more complex: Who did you play with? Who did you play against?
RAPM (Regularized Adjusted Plus Minus) was refined by Washington Wizards analyst Joe Sill to temper extreme APM values by pushing them closer to zero. The “problem” with the RAPM was, according to Jeremias, that a starting value of zero was attached to each player, regardless if you’re LeBron James or someone way wors
xRAPM adds a starting value for each player, based on individual stats: “ “the standard box score, data that is extracted from play-by-play – like block and steal type – and other information like shot defense, deflections etc.” This information is then blended with the lineup algorithm to create xRAPM.
Why Add Individual Player Data?
Beyond the obvious value of individual numbers, Jeremias provided an example common in the NBA: “Suppose Rudy Gobert and Jaden McDaniels are always on the court together. And when they’re subbed out, they’re both subbed out. APM [as well as RAPM] is incapable of telling you whether it’s Gobert or McDaniels who makes the defense better.” By incorporating individual player data, xRAPM addresses this limitation.
What’s Inside the “x” of xRAPM?
Jeremias doesn’t reveal his exact formula for obvious reasons, but he explained that he selects which stats to include in the algorithm, while the algorithm itself determines how heavily each stat is weighted. For instance, “If a stat appears to contribute little value, the algorithm may factor it close to zero,” he said.
How Do Spurs Legends Fare in xRAPM?
The short answer: Even better than you might expect. xRAPM ranks Tim Duncan as the best player in the league from 2001 to 2003, second in 2004, 2005, and 2007, and third in 2000. Meanwhile, David Robinson is ranked the number one player in 1999 (largely for his defensive impact) and remains in the Top 10 until 2002.
However, the most beautiful thing about xRAPM, from a Spurs perspective, is how it sees whom many among us probably believe is the most underrated player in our time of watching NBA basketball. And that is Manu Ginobili. Manu came in eleventh in xRAPM as early as 2004 – and he cracked the Top 10 eight times in the years that followed. And though you’ll not like everything that you’ll see in the 29 years xRAPM (since play-by-play data has been tracked), you’ll love it that Manu has made even that Top 10 (amongst two other former Spurs).