The Player Efficiency Rating (PER) was developed by ESPN statistician John Hollinger as a single-number summary of a player's per-minute production across all phases of the game. The approximated PER (aPER) computed here uses Hollinger's original linear weighting of twelve box-score categories, normalised per minute, to produce a comparable efficiency score with no additional data required beyond a standard box score.

How the aPER Formula Works

At its core, aPER is a weighted sum of positive contributions (makes, assists, rebounds, steals, blocks) minus negative contributions (misses, turnovers, fouls), divided by minutes played. The coefficients were derived by Hollinger to reflect each stat's approximate impact on scoring margin. A made field goal (+85.910) carries the largest single positive weight because it directly adds points to the scoreboard. Steals and turnovers carry equal and opposite coefficients (±53.897), meaning that every steal exactly cancels one turnover in the formula.

Per-minute normalisation is the most important feature of PER. By dividing the weighted sum by MP, the formula makes efficiency comparable across players with very different roles. A sixth man who logs 18 high-efficiency minutes can score higher than a starter who logs 36 mediocre minutes. This per-minute framing also means that the same box-score line in fewer minutes yields a higher aPER — a useful corrective against counting stats that reward volume over quality.

Interpreting the Six Performance Tiers

The league average aPER is approximately 15.0, which defines the boundary between Below Average and Solid Rotation Player. Each step upward requires meaningfully better per-minute production: the Borderline All-Star tier starts at 20.0, All-NBA at 25.0, MVP Caliber at 30.0, and All-Time Great at 35.0. Only a handful of players in history have sustained aPERs above 35 for a full season — the most commonly cited examples include peak Michael Jordan, peak LeBron James, peak Shaquille O'Neal, and Giannis Antetokounmpo's MVP seasons.

An important calibration note: single-game aPERs are noisier than season-average aPERs. A player who shoots particularly well or records an unusual number of blocks in one game may post an aPER that overstates their typical efficiency. Season-average inputs (points, rebounds, assists, etc. per game divided by minutes per game) produce a much more meaningful and stable measure of true efficiency.

Limitations and When to Use Other Metrics

aPER does not account for pace, defensive rating, or team context. The official Hollinger PER applies a pace adjustment so that players on fast-paced teams are not mechanically rewarded for more possessions per minute. The linear aPER here omits that adjustment, which can slightly inflate ratings for players on up-tempo teams. Additionally, aPER is entirely box-score-based: it cannot capture off-ball positioning, screening quality, defensive rotations, or other actions that show up in video analysis but not the box score.

For broader evaluation, complement aPER with Box Plus/Minus (BPM), which uses the same box-score inputs but adds an adjustment for team performance, or with RAPTOR and EPM, which incorporate on-off data and shot-quality tracking. None of these metrics should be used in isolation — a complete player evaluation combines aPER, advanced on/off metrics, and qualitative scouting to build a full picture.