What is BPM in basketball?
BPM — Box Plus/Minus — is a box-score-based estimate of a player's contribution per 100 possessions, relative to a league-average player. Zero is average, +5 or better is an All-NBA-caliber season, and around −2 is replacement level. Basketball Reference publishes BPM back to the 1973–74 season, split into offensive (OBPM) and defensive (DBPM) halves.
What BPM tries to measure
BPM starts from a simple question: given only what's in the box score — scoring, efficiency, rebounds, assists, steals, blocks, turnovers — how much did this player help his team per 100 possessions? Because it's expressed relative to league average, it travels across eras better than raw counting stats: a +6 season means roughly the same thing in 1985 and 2025 even though pace and scoring environments differ wildly. Its main limitation is honest and well known: the box score can't see everything, and defense in particular is only partially captured, which is why DBPM is treated as an estimate rather than gospel.
How TRUE 82 uses BPM-style value
In TRUE 82, every player-season's core value is built mostly from OBPM and DBPM, with some minor custom tweaks. That's also why the player pool starts in 1974 — the steals, blocks, and turnovers those stats depend on weren't tracked league-wide before then. One adjustment worth naming: shooters from the low-3PT and pre-3PT eras get shooting credit based on reputation and vibes, because the 1978 box score cannot tell you that a player would happily launch eight threes a game today.
Why BPM alone is not enough
Five high-BPM players are not automatically a great team — value overlaps. That's why the TRUE 82 engine layers fit on top of value: it taxes lineups where too many players need the ball, checks whether there's enough shooting to keep the floor spaced, and penalizes a backcourt or wing rotation that can't defend. BPM tells you how good a player was; the engine decides whether your five would actually work together for 82 games.
Play a BPM-driven draft game
The fastest way to build intuition for advanced metrics is to draft with them. TRUE 82 deals you random franchise-and-era tickets and lets the engine judge the result — free, in the browser, no account.
BPM and its underlying data are the work of Basketball Reference / Sports Reference LLC. TRUE 82 is an independent fan project and claims no endorsement by or affiliation with Basketball Reference, Stathead, or Sports Reference LLC.