Offensive Performance, Omitted Variables, and the Value of Speed in Baseball

This note considers the problem of estimating the marginal products of offensive events towards a baseball team's objective of scoring runs. Regression techniques on official statistics give a positive marginal product for a stolen base attempt, which is inconsistent with the theory of mixed strategy Nash equilibrium. Augmenting the specification of the production function to include other productive qualities of footspeed restores estimates consistent with equilibrium theory.