Baseball Judgments

Baseball Judgments |
2001*: A steroid odyssey


By Roger Weber


Calls for an asterisk next to any Barry Bonds record resonate throughout baseball as new allegations of steroid use by the San Francisco slugger appear. And my stats calculations support the idea that Bonds' home run totals were affected by an extra variable, possibly steroids.


Reports claim Bonds began taking steroids before the 2000 season. Bonds' stats through 1999 fit a fairly quadratic model. But the model predicts Bonds would have hit just 33 home runs in 2001, not the 73 he hit to set the single season home run record. Based on further study, the probability of Bonds hitting 73 or more homers that season was about four in 100 million. That's a small number. Not out of the question, but unlikely. That extra variable likely played a role in inflating his stats.


Of Course, Bonds isn't the only slugger whose stats during one season didn't match the rest of his career. Cubs' star Sammy Sosa, the Cardinals' Mark McGwire and former Yankees' outfielder Roger Maris far overshot their ranges of likely home run totals, all by at least 11 home runs, during their best home run hitting seasons.


McGwire and Sosa may have also been affected by steroids. Maris hit his 61 home runs in 1961, right after the season increased from 154 to 162 games and right after major leagues expanded and offensive stats exploded as teams found it more difficult to acquire quality pitching.


Baseball improved after 1947 when blacks joined the game. I found that by 1957 play had improved by a few percent from play before integration. Adjustments to the baseball in 1930 increased general home run production by about 6%. These factors all affected home run production for great players, but are rarely focused on as much as steroids, whose effect on baseball cannot yet effectively be determined.


Bonds, Ruth and Maris played in ballparks not very friendly to home run hitters. Bonds' towering shots to right field at AT&T Park in San Francisco had to fight a long fence and harsh bay winds.


While Bonds may have taken steroids and while steroids boost performance, other biases also affect home run production.


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