A valuation system determines in real-time values of plays occurring during games by identifying a play that occurred during a game. The system determines an expectation of scoring prior to the play occurring, and an expectation of scoring that results from the play occurring. The system then calculates a value of the play as the difference between the expectation of scoring that results from the play occurring and the expectation of scoring that existed prior to the play occurring, and any scoring generated by the play.