in 1993, a friend from high school who had become a baseball player's agent told me that Jose Canseco was the Typhoid Mary of steroids: you could see the affect of Canseco's proselytizing steroids on his teammates in Oakland and then in Texas (co-managing director: George W. Bush. Here's my 2004 American Conservative article on Canseco, the Bush dynasty, Andrew Sullivan, and steroids, which came out the year before Canseco's tell-all autobiography).

Ray Fisman in Slate points to a 2007 study by two labor economists confirming Canseco's role spreading steroids around those two teams, plus his later clubs.

Learning Unethical Practices from a Co-worker:The Peer Effect of Jose Canseco Eric D. Gould and Todd R. Kaplan This paper examines the issue of whether workers learn productive skills from their co-workers, even if those skills are unethical. Specifically, we estimate whether Jose Canseco, one of the best baseball players in the last few decades, affected the performance of his teammates. In his autobiography, Canseco claims that he improved the productivity of his teammates by introducing them to steroids. Using panel data on baseball players, we show that a player’s performance increases significantly after they played with Jose Canseco. After checking 30 comparable players from the same era, we find that no other baseball player produced a similar effect. Clearly, Jose Canseco had an unusual influence on the productivity of his peers. These results are consistent with Canseco’s controversial claims, and suggest that workers not only learn productive skills from their co-workers, but sometimes those skills may derive from unethical practices. These findings may be relevant to many workplaces where competitive pressures create incentives to adopt unethical means to boost productivity and profits.

Canseco's outgoing personality contrasted with the more furtive and even anti-social personality of later steroid users, such as Barry Bonds, who introduced Gary Sheffield to his training methods, but who basically didn't like his teammates.

A couple of years ago I wrote, "You'll notice that the topic of art forgery is more interesting to philosophers than to art historians, who would prefer not to think about it. Philosophers like to ask questions like, 'If this small sketch was so beautiful it was worth a million dollars when it was a Raphael, why isn't it worth anything now that it's a Hebborn?'"

The basic motivation of art historians and of baseball historians, such as Bill James, is hero worship. Thus, art historians don't like to think about how many famous paintings are, in whole or in part, forgeries, while Bill James did everything he could to avoid thinking about the impact of steroids on his beloved baseball statistics.

Of course, there's also the crass financial conflict of interest: James finally got himself a nice job with the Boston Red Sox, whose two best hitters, Manny Ramirez and David Ortiz, were juicers. If he'd been sounding the alarm about steroids for years, would he have gotten that job? The same questions can be asked about museum curators.