The Danger Of Statistics: A-Rod Pitch Tipping Edition

The statistical revolution in the field of baseball analysis can be nothing but a good thing. More precise metrics have allowed us to gain a better understanding of the game and learn how to better evaluate players and performances. However, this has also led to some amateur statisticians using these numbers incorrectly to reach certain conclusions that are accepted as true when they are, in fact, not grounded in reality. Steve Lombardi of Was Watching posted such a misuse of numbers from 3-D Baseball this morning. It was a study which claimed to definitively show that opposing middle infielders benefited greatly from having A-Rod at short in blow out games, thereby proving that Alex was giving them the signs. Go read the study and see if you can find the flaws before reading further.

I am sure that you picked up on the major problem. The study does not control for Texas!! Go look at the Texas ‘ pitching staff OPS against for that season- its .856. I do not know what those hitters did against Texas for the season, but I bet it was considerably better than they did against almost everybody else. Furthermore, the study ignores another bias inherent in the data- the pitchers throwing at that point are likely to be the dregs of MLB. Mop up work for the worst pitching team in baseball generally is not done by pitching virtuosos. This is a fatally flawed study. Yet all that people will quote from it is the following:

That’s nearly .100 points in OPS, in a full season’s worth of PAs, that these hitters gained from having A-Rod in the field late in lopsided games, and that’s not even accounting for the fact that they’re supposed to be hitting worse in these situations. They basically morphed from Joel Youngblood into Dave Parker at the plate. Or from Adam Kennedy into Miguel Tejada. What’s more, they should have been dropping to Mark Lewis levels instead. Notice especially the huge jumps in SLG: these hitters were flat out clobbering the ball like they knew what was coming. It’s not like those pitchers in Texas needed any extra help without “Crash” Rodriguez screwing with their ERAs either. I hate to say it, but it’s pretty clear from these numbers that something was up. This is beyond grey area even. And it’s not something he was just following the rest of baseball into. This is purely someone being an ass all on his own.

That is just irresponsible.

Related posts:

1. Apparently Pitch-Tipping Does Not Work
2. MLB will expand A-Rod probe to include pitch tipping
3. Doug Glanville: Pitch Tipping Report Mistaken
4. A-Rod and the Pitch Tipping Accusation
5. Young, Brantley: Pitch-Tipping Allegations Ridiculous