When Jose Canseco finally came clean as the "Godfather of Steroids" in 2005, his use of performance-enhancing drugs had already been a matter of speculation for nearly two decades. In his tell-all biography, Juiced, Canseco alleged that he schooled many of his power-hitting teammates on integrating steroids and growth hormones into their training regimens, including such baseball greats as Mark McGwire and Jason Giambi. Yet given his earlier denials of steroid use, his credibility was tenuous.
Now, a couple of Israeli economists, Eric Gould and Todd Kaplan, have released a study backing up Canseco's claims that he was "The Chemist" of baseball. Their work shows how the careful use of data can be an important tool in ferreting out drug use in baseball and other sports. They analyze the performance of Canseco's teammates—the players who had access to his locker-room pharmacy and expertise—and find that after playing with Canseco, players hit more home runs and otherwise boosted their numbers in the areas most affected by steroid use. Sometimes data speak more credibly—if not louder—than words.
Gould and Kaplan are labor economists, not baseball fans. Their primary interest in studying Jose Canseco's influence is in illustrating the sorts of pernicious behavior that can be learned in the locker room, by the water cooler, and in the workplace more generally. A few years ago, for example, there was a pair of scandals involving large numbers of false disability claims at the Long Island Railroad and the Boston Fire Department. (The Boston case broke when one of the purportedly disabled firemen placed eighth in a national bodybuilding competition.) In both cases, fraudsters possibly learned the benefits of cheating—and maybe even the details of how to do it—from their co-workers. Being around other cheaters also provides the ready excuse we've all heard before (and used ourselves): "Everyone's doing it." You'd be a chump not to get disability payments while everyone else is relaxing by the pool or to lose baseball games to competitors who have an unfair edge.
To provide a statistical assessment of Canseco's alleged influence, Gould and Kaplan compared the performances of every hitter and pitcher who played with Canseco, and analyzed how they changed after exposure to him. Focusing on the power-positions players—catcher, first base, outfield, and designated hitter—who would most benefit from extra heft and bulk, Gould and Kaplan found that contact with Canseco was worth an extra two home runs per year in the seasons that followed. Canseco's teammates also saw increases in other power statistics—half a dozen extra runs batted in per season, a one-point boost to slugging percentage, and a handful of additional walks. Meanwhile Canseco did not seem to help teammates in their fielding, base-stealing, and other nonpower areas. (In results not reported in the study, Gould and Kaplan also found that pitchers were able to put in more innings when exposed to Canseco, another indication of The Chemist's hand in helping his teammates work harder and longer.)
Of course, it's possible that Canseco's outsize influence could be benign—maybe he shared with his fellow power hitters a set of batting tips that proved effective. But if this is the case, Canseco's abilities as a hitting instructor were quite unique—Gould and Kaplan looked at the effect 30 other power hitters of Canseco's era had on their teammates and found that none of them had a statistically significant influence on the hitting performance of teammates. (Some of these were in fact Canseco's original disciples, suggesting, perhaps, that not all users become proselytizers.) What's more, the Canseco effect disappears after 2003, when baseball instituted random drug testing and punishments for those found guilty. If Canseco was merely offering innocent performance-enhancing advice, it stopped working with the advent of drug testing.