TDA Bullpen - Our Writers' Blog

Tuesday, April 27, 2004

My article on Pete Rose and greenies seems to have hit a nerve. I got a good amount of e-mail basically saying that people should just leave to poor man alone. Another line of thought is "How much could greenies help you? Steroids can help you add 20 pounds of muscle to your body, but how large an effect do greenies have?"

The answer is simple. I don't know. There's never been a peer-reviewed double-blind study with a sample size large enough to give a good measurement. We do know that many baseball players took them in the 1960s and 1970s. They seemed to think that they had some effect. How large, if any? Again, we have no way of knowing for sure.

On the other hand, we do know how many more hits Rose had than Cobb. Pete finished with 4256 to Ty's 4189 (that's what baseball-reference.com says, I'll trust them). Okay, get out Mr. Calculator. Pete had 67 more hits, divide by a little more than four thousand, and we get 1.6% In other words, if greenies had a 2% positive effect on getting hits, then that covers Rose's margin.

How much would a two percent effect be? Well, in a typical Pete Rose season you could pencil him in for about 210 hits, so 2% would mean roughly 4 hits. In other words, an extra hit every six weeks.

Could greenies have an effect so small that they just get swamped in the noise? Well, if there's one thing we can say about Pete, it's that he gave us a large sample size. Charlie Hustle had 14052 career ABs, and a batting average of .303. Treating this as a binomial distrbution, the variance would be 14502 * (.303) * (.697). Taking the square root of this results in 55. So the noise on Rose's hits comes in at roughly 1.3%, so if greenies were even a 2% effect, they weren't being submerged in random chance.

Pete Rose's 4256 is like Gaylord Perry's 314 wins, or for that matter, Jose Canseco's MVP trophy. Those are all in the books, and nobody has made a fuss to change history. That's the precedent we should be looking at.

posted by David 1:24 AM