A published formula
As published on the product
45% production percentile, 25% player win rate, 20% winning-output share, 10% court share. Box impact = PTS + 1.2 × REB + 1.5 × AST. Qualified: at least 10 appearances or 250 minutes.
Because the weights are published, you can see exactly why a player ranks where they do: a high score can come from production, from winning, or from a large share of a winning team's output.
What it is not
The product states it plainly: WinBA is not a causal estimate of wins added, and it is not a betting pick. It is a descriptive composite — useful for comparison, not for prediction on its own.
Limitations
Composite scores inherit their weights' judgment calls. Win-rate components also credit players for teammates' quality. Read the components, not just the total.