Methodology
BOX+
points per 100 possessions raw, ARC units normalised
Box+ = ( PTS + 0.727·AST − 2.052·TOV + 1.080·OREB + 2.138·STL + 0.579·BLK + 0.100·DREB − 0.862·PF + charge ) per 100 possessions, × poss/(poss + 2500)Box+ is the expected point value of what a player’s box score records. Every recorded action is priced at the consequence measured for it in play-by-play, summed and divided by possessions.
The prices come from 2016-2025 play-by-play, pooled and season-independent, and are applied to all 29 seasons. A turnover costs 2.052 because it forfeits the team’s own attempt (0.993) and hands the opponent his next one (1.059). A steal is worth 2.138 because the attempt that follows a live-ball turnover is worth more than an ordinary one (1.145). A block is worth 0.579, following a 0.583 defensive recovery rate, and an offensive rebound 1.080, the value of continuing a possession after a miss. An assist adds 0.727, the pooled surplus of points created over an ordinary terminal attempt. A defensive rebound is worth 0.100, because most are uncontested.
Box+ does carry an efficiency term. The charge is 3.0 · (TS − league TS) × true-shooting attempts per 100 × (usage / league usage), discounted on thin shooting samples, so scoring above league efficiency is paid in proportion to volume and scoring below it is charged the same way. Removing the charge costs 0.046 of next-season predictive correlation.
Both series are published: raw in points per 100, and normalised into ARC units by an affine per-season map whose scalars are fitted from the board itself. On the 2025-26 board the normalised half is c_box = 0.1639·Box+ − 2.2918, r = 0.999997.