A Quantile Regression Approach to All Runs Are Created Equal

In 2003, the book Moneyball by Michael Lewis claimed that certain performance metrics (such as walks and on-base percentage) were being undervalued in the Major League Baseball (MLB) labor market in the years prior to the book’s publication. According to Moneyball, the Oakland Athletics were able to construct a competitive roster despite being a small market team due to the team’s recognition and exploitation of these statistics in the MLB labor market. Previous research on the topic has yielded mixed results on whether an inefficient market truly existed prior to the publication of Moneyball and whether a labor market correction took place in the post-Moneyball period. This paper extends previous research by utilizing a quantile regression approach to investigate these questions at the different levels of the free agent player salary distribution. Additionally, this paper uses the approach proposed by Lindsey (Oper Res 11(4): 477–501, 1963) and applied by Pinheiro and Szymanski (J Sports Econ 15270025221085712, 2022), to structurally measure player performance through the run value contribution of the player. Using the timeframe 1997–2016, we find that the MLB labor market for skills was largely efficient both before and after the book’s publication at the different levels of the salary distribution, refuting the central claim of Moneyball.