Psych, Psych, Super-Psych

I hadn't read this when it came out originally, but the HardballTimes had an article investigating the "hidden" effects of having a base-stealer on first as it relates to disrupting the pitcher. Here's the wrap-up:

"The goal of this study was to confirm or refute the notion that good base stealers disrupt the opposing pitcher/defense simply by his presence on first base. I reasoned that any disruption would show up in the performance of the batters who came to the plate with a Stealer on first base. I studied the performance of 219 batters (almost 3700 plate appearances) when one of the top 10 base stealers was on first base (with second base open) and compared that to what would be expected from those particular hitters. I then used a custom hit-trajectory matrix to convert the Stealer-on-first base performance into a defense-independent context that can be compared to the generic case. Finally, a small correction for pitcher quality was found to be necessary.

The results obtained indicate a small effect of disruption, amounting to about 0.17 in RC27, for the Stealer on first base situation. An independent cross-check was made considering what happens with any runner on first and again a very small effect of disruption was found (0.07 runs per game for that check). Finally, I found that pitchers hit a few more batters than expected when a Stealer was on first, although the effect was not statistically significant. It could be real, but we can't say for certain. Pitchers do commit more balks with a Stealer on first base.

Assuming these small effects are real, how much are these base stealer intangibles worth over a season? A typical Stealer is on first base for 180-220 plate appearances per season. That corresponds to about 128 outs (for this group), which adds up to 4.75 games. Assuming the improvement due to disruption is 0.17 runs per game, this gives a measly 0.8 runs over the whole season. Let's throw in an extra balk and a half-HBP (I didn't include the HBPs in the OBP calculation for simplicity) and we get an additional 0.5 runs (more or less), for a grand total of about 1.3 extra runs a year.
So, the next time you tune into the White Sox game and Hawk Harrelson is telling you that "Scotty" Podsednik, by virtue of his ability to disrupt the pitcher, is worth more than what his statistics show, well you now know he's telling you the truth. Podsednik is worth a little over one more run per season."

Since the 3,700 PA sample size was a bit small, it was expanded to the top 20 base-stealer.

"The result I found is a little more stringent: the 3.2 runs per season number goes to about two runs per season. So, instead of saying that Podsednik adds a little over one run per season due to his "disruptive" powers, we must content ourselves with saying that he very likely adds no more than two runs per season. "

This is a result that I've known to be true for a while (the "disruption factor" is very small overall) but it is interesting to see it quantified. Two runs is not insignificant (10 runs are about one win) but it is clearly hyperbole when the commentator goes on and on about how Brian Roberts is psyching out the pitcher. Now you'll know the truth. And isn't that really what we're after?

[I really wish I could do this kind of in-depth analysis. I guess I'll have to settle for understanding and appreciating it.]