Editors note: This story is part of a Feature "The Doping Dilemma" from the April 2008 issue of Scientific American.

A game theory model of doping in cycling applies to other sports as well, particularly baseball. For expert insight, I spoke with Lance Williams, an investigative reporter with the San Francisco Chronicle and co-author (with Mark Fainaru-Wada) of Game of Shadows, a revelatory book about how BALCO, the Bay Area Laboratory Co-Operative, supplied baseball players and other athletes with performance-enhancing drugs. When I outlined my ideas about how game theory explains massive cheating in sports, Williams backed up virtually every point: “Athletes have a huge incentive to dope. There are tremendous benefits to using the drugs, and there is only a small chance that you will get caught. So depending on your sport and where you are in your career, the risk is often worth it. If you make the team, you’ll be a millionaire; if you don’t, you’ll probably go back to driving a delivery truck.”

Once the top competitors in a sport begin cheating, the rule breaking cascades down through the ranks until an entire sport is corrupted. In Williams’s estimation, based on wide-ranging reporting and numerous interviews with athletes, coaches, trainers, drug dealers and drug testers, between 50 and 80 percent of all professional baseball players and track-and-field athletes have been doping. Given that reality, Williams explained, for many athletes not only is doping not cheating, it is necessary. To illustrate his point, Williams cited Charlie “the Chemist” Francis, coach of the sprinter and (briefly) the 1988 Olympic gold medalist in the 100-meter run, Ben Johnson, who was busted for doping and stripped of his medals. The doping was “completely self-defensive,” Francis told Williams. “It was cheat or lose.”

How can leagues and governing bodies change the incentives in the game matrix for baseball? Williams suggested stronger penalties against both individual athletes and entire teams, along with stiffer legal sanctions. Ironically, Williams and Fainaru-Wada personally felt legal heat for refusing to reveal their sources to federal authorities: “We stood to serve more time behind bars [both faced 18-month sentences] than any of the steroid dealers convicted in the BALCO conspiracy and any of the athletes we reported on, including [longtime San Francisco Giants slugger] Barry Bonds.” You know a system is corrupt when the messenger is shot and the gun makers walk.