Purpose: In baseball, a run scored on offense carries the same on-field (win) value as does a run prevented on defense. Both outcomes bear the same score margin implication. This presumption of unit equality is implicit in the Wins Above Replacement (WAR) measure, which treats units of...

Ferraro and Taylor (2005) asked 199 professional economists a multiple-choice question about opportunity cost. Given that only 21.6% answered “correctly,” they conclude that professional understanding of the concept is “dismal.” We challenge this critique of the profession. Specifically,...