seniorGame Theory
What is Shapley value in cooperative game theory?
Updated May 16, 2026
Short answer
Shapley value fairly distributes total payoff among players based on marginal contributions.
Deep explanation
It computes each player's average marginal contribution across all possible coalitions. It satisfies fairness axioms: efficiency, symmetry, dummy player, and additivity. It is widely used in ML explainability and coalition games.
Real-world example
Used in explainable AI to attribute model predictions to features.
Common mistakes
- Ignoring computational complexity in large player sets.
Follow-up questions
- Why is Shapley value expensive to compute?
- What is marginal contribution?