The Possible Effect of Steroids on Home-Run Production

36 IN A RECENT paper entitled “On the Potential of a Chemical Bonds: Possible Effects of Steroids on Home Run Production in Baseball,”1 physicist Roger Tobin develops a systematic analysis showing how performance-enhancing drugs (PEDs) taken by an already highly skilled player could produce a dramatic increase in home-run production. Tobin starts by looking statistically at home-run production during the “steroid era” (1994–2003) compared to earlier eras. The number of home runs hit by a player is the product of balls in play and home runs per balls in play (HRBiP). Tobin argues that the former involves skills and strategies that are not likely affected by PEDs. He therefore takes HRBiP as his metric for comparing home-run production in different eras. In figure 2 of his paper, he shows that, for elite home-run hitters in the pre-steroid era (Aaron, Ruth, Mays, Killebrew, Robinson), HRBiP was approximately 0.10, whereas for hitters in the steroid era (Bonds, Sosa, McGwire, Griffey, Palmeiro) the number jumped to 0.15, a 50 percent increase. Tobin then investigates whether it is plausible that such a large increase can be attributed to PEDs. In section 2, entitled “What Do Steroids Do?” he presents lots of evidence from the scientific literature justifying his starting assumption for the remainder of the analysis. Namely, he assumes that the main effect of steroids vis-à-vis home-run production is to increase the batter’s muscle mass by 10 percent. Since I have no expertise in this area, I will simply take it as a reasonable starting point. Tobin next develops section 3, entitled “How Much Can More Muscle Enhance HomeRun Production?” This section is really the heart of the paper and the one I will discuss at length. Tobin’s chain of reasoning involves two distinct steps: