Does swinging at the pitch really protect a base-stealer?
May 28, 2007 21 Comments
Another one of those things I tend to over-hear on the radio: When a runner is trying to steal, the batter should swing, as this will disrupt the catcher and give the runner a better chance of stealing. Here’s to ye olde baseball conventional wisdom, the starting point of many a Sabermetric writing. Fair enough. Let’s see if this one stands up to the evidence. First, I isolated all instances of a stolen base or caught stealing, either of 2nd or 3rd in 2006, absent pickoffs. (As always, thanks to Retrosheet for the fact that I have a gig… and that I haven’t yet finished my dissertation.)
I looked at what the batter did on the pitch that came to the plate while the runner attempted to steal and classified it either as a swing (swinging strike or missed bunt), or a non-swing (either a ball or a called strike). I also classified pitches as either strikes or balls. Needless to say I also looked at whether the runner was safe at second (or third). The rest was just a matter of a few chi-square analyses.
Does swinging “protect” a base-stealer? Far from it. If the batter swung at the pitch while a runner attempted to steal 2nd, the runner was safe 65.7% of the time, while if he didn’t the success rate was 77.9%. Looking at a runner stealing third, the same finding emerged. When the batter was not swinging, the runner was safe 82.1% to 56.8% for the swingers. Both chi-squares were significant. Apparently, conventional wisdom has been wrong for a while, although players only swing about 19.8% of the time in this situation, so perhaps the “wisdom” is more present in the press box than on the field itself.
This is a strange finding though that needs some explanation. The fact that a relationship has been found does not mean a cause has been found. For example, it’s possible that batters are more likely to swing and miss (in this case, all swings missed. A foul ball would have returned the runner to the original base and a ball in play would not have resulted in a stolen base) at well-placed pitches and that those well-placed would be more easily used to gun down the would-be base stealer. Let’s take away the swing for a moment, and look at whether on non-swinging responses, whether the pitch was called a ball or strike made a difference on the runner’s fate when he tried to steal second. On balls, the runners’ success rate was 78.5%, while on called strikes, it was 76.3%. Chi-square was not significant, indicating that in this data set, it makes no difference statistically whether the pitch was called a ball or a strike. Now, this doesn’t disprove the original conjecture. Perhaps balls that are swung at and missed are a different breed altogether (more likely to miss a fastball?) or perhaps those that are swung and hit are the oddballs (pardon the pun). There could be a bias in which pitch types end up in the catcher’s glove and they might be biased in the direction of easier throws to second. There might also be pitches which are easier for the runner to read (and get a good jump on) and which are less likely to be swung at (or more likely to be hit when they are swung at).
Another factor floated in such discussions is the handedness of the batter. Most catchers are right-handed, and naturally spring out toward the left-handed batters’ box when making a throw to second. Perhaps if that box is occupied by a left-handed batter, the catcher will show some ill effects of this “obstacle.” The answer is no. Success with a lefty in the batter’s box was 76.1% and with a righty, it was 75.0%. No significance in that association. For a throw to third, there is an advantage to the runner for having a right-handed hitter in the batter’s box (80.6% to 67.7%). In that case, a right-handed batter is more directly between the catcher and third base.
To be honest, I’m confused. I don’t know what to make of this finding. Why would a batter’s swinging actually make it easier for the catcher to throw a runner out? Perhaps the batter is more of an obstacle standing there after not having swung than if he had swung. But, for what it’s worth, a reminder that one should never take accepted wisdom in baseball (or anything) without asking to see some proof.