A fair way to split the credit/blame for the score among the 13 factors — each factor gets exactly its marginal contribution.
Shapley 1953 game-theoretic value: across all permutations of factor inclusion, what's factor X's average marginal contribution to the final composite? This gives a cleaner attribution than simple "factor i has weight w_i × score" because it accounts for factor interactions. The Score Composition waterfall on every ticker page shows Shapley contributions.