Is EFF a real metric?
Yes. Efficiency (EFF) is a long-standing box-score rating used by the NBA: positive contributions (points, rebounds, assists, steals, blocks) minus misses and turnovers.
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Player Efficiency Impact Calculator
The standard NBA efficiency (EFF) rating from a box-score line — positive contributions minus misses and turnovers.
EFF = (PTS + REB + AST + STL + BLK) − (missed FG + missed FT + turnovers)
Frequently asked questions
What are its limitations?
It rewards volume and can flatter players who shoot a lot, and it undervalues defence and efficiency. Advanced metrics like PER and BPM try to fix that, but EFF is simple and transparent.
Why subtract missed shots and turnovers?
Because they are wasted possessions that hurt the team. Counting only the good stuff would reward a player who scores 20 but misses 25 shots, which EFF rightly penalises.
Can I use per-game or season totals?
Either, as long as you are consistent. Per-game is best for comparing players; season totals show cumulative contribution.
What is a good EFF?
Star players often post per-game EFF in the mid-20s and up. Compare within the same league and era for it to mean much.