# Player efficiency rating
The player efficiency rating (PER) is a single-number statistic for basketball players, created by analyst John Hollinger, that sums a player's positive box-score accomplishments, subtracts the negative ones, and returns a per-minute, pace-adjusted rating of performance[1](https://www.basketball-reference.com/about/per.html). In Hollinger's own words, "The PER sums up all a player's positive accomplishments, subtracts the negative accomplishments, and returns a per-minute rating of a player's performance"[1](https://www.basketball-reference.com/about/per.html). The scale is fixed by construction: the league average is always 15.00, so a value above 15 indicates above-average per-minute production in that season[2](https://sportsmonkie.com/what-is-player-efficiency-rating/).
| Key fact | Detail |
|---|---|
| Creator | John Hollinger, who developed PER while applying principles of economics to basketball statistics[3](https://espnpressroom.com/feature/how-hollinger-crunches-the-nba/) |
| What it measures | Per-minute productivity from the box score, with credits for made shots, rebounds, assists, steals, and blocks and deductions for missed shots, turnovers, and fouls[1](https://www.basketball-reference.com/about/per.html) • [4](https://zencalculators.com/sports/basketball_stats) |
| Scale | Pace-adjusted and rescaled so the league average is 15.00 every season[2](https://sportsmonkie.com/what-is-player-efficiency-rating/) |
| Historical coverage | Basketball-Reference computes PER for all players since minutes were first recorded in 1951-52; Hollinger's own database went back to 1988-89[1](https://www.basketball-reference.com/about/per.html) |
| Example leaders | In 2010-11, LeBron James led the NBA at 27.34 PER; MVP Derrick Rose ranked ninth at 23.62[3](https://espnpressroom.com/feature/how-hollinger-crunches-the-nba/) |
| Main limitation | It is built entirely from the box score, so it does not measure defensive impact directly and treats garbage-time production the same as clutch production[5](https://blog.statsbench.com/player-efficiency-rating-explained/) |
## Origin
**John Hollinger** built PER out of a self-described personal need to answer questions the traditional statistics did not address. A [University of Virginia](https://www.edgepedia.org/university-of-virginia) graduate with a double major in economics and environmental science, he started the website Alleyoop.com in 1995 and applied concepts such as opportunity cost and marginal cost to player evaluation[3](https://espnpressroom.com/feature/how-hollinger-crunches-the-nba/). He has said that reading the baseball analyst [Bill James](https://www.edgepedia.org/bill-james) as a teenager showed him a different way to look at a game and provided ideas he could apply to basketball[3](https://espnpressroom.com/feature/how-hollinger-crunches-the-nba/).
PER brought Hollinger his first professional break, a position as an online sports editor at The Oregonian in 1998. He later became basketball editor at SI.com and wrote his first book, *Pro Basketball Prospectus*, in 2002. He joined ESPN.com in 2005, where he wrote the weekday "PER Diem" column during the season and continued to refine his statistical formulas[3](https://espnpressroom.com/feature/how-hollinger-crunches-the-nba/). He later moved into team management as vice president of basketball operations for the [Memphis Grizzlies](https://www.edgepedia.org/memphis-grizzlies)[6](https://time.com/3933658/harvey-pollack-hoops-stats-guru/).
## How it is calculated
PER is a linear-weights formula: every box-score event receives a coefficient, and the weighted sum is divided by minutes played. Basketball-[Reference](https://www.edgepedia.org/reference), which maintains the published calculation, begins with an unadjusted value called uPER, computed from field goals, three-pointers, free throws, assists, turnovers, rebounds, steals, blocks, and minutes, together with team and league factors such as the value of a possession[1](https://www.basketball-reference.com/about/per.html).
The unadjusted rating is then adjusted for pace, so that players on teams that play fast or slow are compared on a common basis, and finally rescaled so the league average lands at 15.00[2](https://sportsmonkie.com/what-is-player-efficiency-rating/). The formula credits every positive box-score event and subtracts the costs of trying: missed shots, turnovers, and personal fouls[4](https://zencalculators.com/sports/basketball_stats). Hollinger set the weights in an attempt to value statistics in the proportion that they help a team win[7](https://sports.stackexchange.com/questions/13810/how-did-hollinger-come-up-with-his-per-formula).
Some inputs have a shorter history than the statistic's coverage. Player turnovers were first recorded in the NBA in 1977-78, and Basketball-Reference supplies estimated values for seasons in which underlying data are missing; for seasons where actual pace adjustments can be computed, the root mean square error of those estimates is 0.01967[1](https://www.basketball-reference.com/about/per.html).
## Reading the scale
Because the league average is pinned at 15.00 each season, PER allows comparison across eras and across players with very different minutes. A reserve and a starter can be compared directly, since the number is per-minute rather than per-game; per-game figures understate bench players simply because coaches give them fewer minutes[8](https://www.nbastuffer.com/per-game-stats-understate-bench/).
The statistic was one of the first basketball measures to adjust for pace of play, adjust for playing time, and normalize results across seasons[9](https://medium.com/data-science/problems-with-per-in-the-nba-fa0e611543e2). Elite seasons reach the mid-20s and above: James's 27.34 led the league in 2010-11[3](https://espnpressroom.com/feature/how-hollinger-crunches-the-nba/), and in January 2017 [Giannis Antetokounmpo](https://www.edgepedia.org/giannis-antetokounmpo), at 22, held a 28.8 PER, the best for a player his age since the three-point shot was introduced[10](https://as.com/us/us/2017/01/07/masdeporte/1483772036_822606.html). In the 2025-26 season, [Kevin Durant](https://www.edgepedia.org/kevin-durant) posted a 21.1 PER[11](https://www.basketball-reference.com/leagues/NBA_2026_advanced.html).
## Limitations
**The box score is the ceiling.** PER is computed only from counted events, so it cannot see much of defense. It does not capture how a defender changes opponent shot selection or shooting percentage, effects that tracking data and plus-minus methods were later developed to measure[5](https://blog.statsbench.com/player-efficiency-rating-explained/). A high PER from garbage-time minutes reads the same as a high PER from clutch minutes, because the formula has no context for when production occurred[5](https://blog.statsbench.com/player-efficiency-rating-explained/).
The weights also reward volume production in ways analysts have criticized. A player producing efficiently on a small shot diet may see that efficiency not survive a larger workload against prepared defenses, a caution that applies to any per-minute number[8](https://www.nbastuffer.com/per-game-stats-understate-bench/). For these reasons, PER is generally treated as a first read on per-minute production rather than a complete measure of player value[12](https://www.hoopstrackr.com/en/glossaire/player-efficiency-rating).
## Place among basketball metrics
PER sits in a family of advanced statistics that includes true shooting percentage, usage rate, win shares, and box plus/minus[5](https://blog.statsbench.com/player-efficiency-rating-explained/). Later all-in-one metrics, such as Box Plus/Minus and Value Over Replacement Player, take different approaches, estimating impact per 100 possessions above a league-average baseline rather than per minute[13](https://pickaleague.com/en/basketball/nba/war). PER remains widely published and well documented, with Basketball-Reference listing it for every NBA season alongside the other advanced columns[12](https://www.hoopstrackr.com/en/glossaire/player-efficiency-rating).
## References
1. [Calculating PER, Basketball-Reference.com](https://www.basketball-reference.com/about/per.html)
2. [What Is Player Efficiency Rating (PER) in Basketball?, SportsMonkie](https://sportsmonkie.com/what-is-player-efficiency-rating/)
3. [How Hollinger crunches the NBA, ESPN Press Room (May 27, 2011)](https://espnpressroom.com/feature/how-hollinger-crunches-the-nba/)
4. [Basketball Stats Calculator - Efficiency (EFF) Rating, ZenCalculators](https://zencalculators.com/sports/basketball_stats)
5. [Player Efficiency Rating Explained (And Its Limits), Statsbench](https://blog.statsbench.com/player-efficiency-rating-explained/)
6. [Appreciation: Harvey Pollack, Hoops Stats Guru, TIME](https://time.com/3933658/harvey-pollack-hoops-stats-guru/)
7. [How did Hollinger come up with his PER formula?, Sports Stack Exchange](https://sports.stackexchange.com/questions/13810/how-did-hollinger-come-up-with-his-per-formula)
8. [Why Per-Game NBA Stats Understate Bench Production, NBAstuffer](https://www.nbastuffer.com/per-game-stats-understate-bench/)
9. [Problems with PER in the NBA, Medium (Data Science)](https://medium.com/data-science/problems-with-per-in-the-nba-fa0e611543e2)
10. [A los 22 años, nadie fue mejor que Giannis Antetokounmpo, AS (2017)](https://as.com/us/us/2017/01/07/masdeporte/1483772036_822606.html)
11. [2025-26 NBA Player Stats: Advanced, Basketball-Reference.com](https://www.basketball-reference.com/leagues/NBA_2026_advanced.html)
12. [Player Efficiency Rating (PER) - Basketball definition, HoopsTrackR](https://www.hoopstrackr.com/en/glossaire/player-efficiency-rating)
13. [Wins Above Replacement (NBA) - Advanced Stats, PickALeague](https://pickaleague.com/en/basketball/nba/war)
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*Topic: Encyclopedia › Sports, games, and recreation › Other team and ball sports › Basketball and court team sports › Basketball rules, techniques, and culture of play*
*Initially written Sep 17, 2026 · Reviewed: Sep 17, 2026; Sep 30, 2026; Oct 21, 2026 · Edited: Sep 17, 2026; Sep 30, 2026; Oct 21, 2026 · Last review: Oct 21, 2026*
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