Player efficiency rating (PER)

Player efficiency rating, developed by analyst John Hollinger, summarizes a basketball player's per-minute statistical production, points, rebounds, assists, steals, blocks, shooting efficiency, turnovers and fouls, into a single number. It is pace-adjusted so players on fast- and slow-paced teams are comparable, and scaled so the league-average player each season scores 15.0.

PER is calculated as a weighted sum of positive box-score actions minus weighted negative ones, such as missed shots and turnovers, divided by minutes played and adjusted for team pace. This differs from a composite value metric such as wins above replacement, which also folds in defensive positioning and, in some versions, uses player tracking data rather than relying only on the traditional box score.

Coaches, media and fans use PER as a quick, single-number way to compare players across teams and eras, in the same statistical tradition as baseball's sabermetrics. Its well-known pitfall is a bias toward high-usage scorers who take a lot of shots and accumulate counting stats, while it undervalues defense, screen-setting, and other off-ball contributions that do not appear directly in the box score, so a high PER does not necessarily mean a player was the most valuable on the floor.