Our results run contrary to the prevailing wisdom. One reason might be that most baseball skills depend primarily upon reaction times and judgments, factors unaffected (or even degraded) by these drugs. Also, in a team sport like baseball, other variables affect individual performance: quality of one’s teammates, home ballpark, changes in the strike zone, injuries and pitching. These factors could mask very slight performance changes like the ones we found.

It is possible (but not addressable by these data) that one effect of drugs is to help players compensate for decline as they age, and thus to extend their careers. But there is no evidence in these data for performance enhancement above previous levels.

And for all of the outrage I keep reading about this article, I’ve yet to see someone correct for these obvious problems. In any event, just from eyeballing the players’ statistics listed in Mitchell Report, I see no obvious impacts.

I mean, this study absolutely requires some kind of baseline or expectation with which to measure players against. Without it, you learn absolutely nothing.

I love the part about Babe Ruth too. His first 6 years he was a PITCHER, so that kind of back-end loads his HR production anyways. Also, his last 6 years were all 2 years younger than Bonds’ last 6 years. Not a huge difference, but imagine if his last 6 years were age 24-29. Obviously you expect someone to produce more HR relative to their career the closer they are to their “prime”.

Anyways, I realize this is a newspaper article and not a peer-reviewed journal article. But if these guys are going to put their titles at the end of it and represent their (good!) schools, I think they should probably make sure their work is methodologically sound. I don’t understand how you can feel comfortable with their findings, given the fact that they controlled for NOTHING in their experiment.

While the age argument is valid, consider that the majority of player start their careers off relatively slow taking upwards of 900 at bats to finally get into their major league groove. That said, while some may have been trying to fetch the fountain of youth, I gather that could be proven incorrect by looking at their post PED statistics – ie when testing occurred.

I just don’t believe that the study these profs have done adds to the evidence either way. Based on the methodology we are no closer to knowing if there was or wasn’t a performance change.

Just because the authors only had 800 words to play with does not mean they couldn’t have done a more comprehensive statistical analysis ie, adjusting for age.

Of course, there are many possible problems with what the authors have provided within the 800 words allotted to the authors by the New York Times. There are also many other way to test the hypothesis that PEDs have no effect on performance. If you want to offer a criticism, proceed to step 3. Until I see another study, I feel safe operating on the assumption that the null hypothesis has not been rejected.

For a start we don’t know the length and intensity of the supposed steriod/ HGH/ whatever plan.

Also when comparing performance one should really compare projected performance to actual performance, that is the correct way to do it. Also, if you are comparing before or after you’ll have to adjust for age (as Richard says). With only 10s of players in the sample the size I suspect will be too small to draw much inference.

I think the only way we can do that is to speculate how his career would have depreciated by comparing him to similar pitchers in their careers. But even then, we can only conclude so much.

It is never easy to value opportunities not taken– ie. Clemens staying clean for the “twilight of his career.”