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Thursday, October 20, 2011
How do leadoff hitters approach the 1st and 9th innings of a tied game?
I took all data from 1993-2010, focusing only when the score is tied, there are no outs, and there are no runners on base. (Not technically leadoff hitters of the inning, but, I don’t want to say “hitters batting with no outs and bases empty”.)
I then split it up by inning, and by home/away. Here are the results:
From innings 2 through 8, the home batters made outs at a rate of 98% of the away batters. In innings 1 and 9, it was 96%.
If I focus on the K rate, home batters K at 99% of the away batters in innings 2 through 8 (range of 92% to 104%), but in the 1st inning, home batters K only 80% of the rate of the away batters.
This pattern repeats itself with walks+hitbatters: innings 2-8, home batters have a rate of 104% of the away batters, but in inning 1, it’s 119%, and in inning 9, it’s 117%.
So, there’s a decided disadvantage to the away pitcher in the 1st inning, in terms of K and BB. Whereas the home pitcher has a K and BB+HB rate of 16.4% and 7.9% respectively, the away pitcher is at 13.2% and 9.4%.
For singles, doubles, triples, there’s a slight uptick in singles in the 9th inning for home batters (relative to the away batters), and a more noticeable downtick in doubles and triples. This is almost surely a function of the fielders playing differently.
The HR rates are a bit more difficult to figure out. Whereas each batting slot is not that much biased in terms of chance of getting a walk or hit, when it comes to HR, that’s not the case. So, in order to properly do this analysis, we’d have to account for at least the batting order, if not the actual identity of the players involved.
In any case, I have the full data, by inning, by home/away, by score, by base/out states, by starter/relief, by day/night, (but not by player identity or batting lineup) so feel free to make some suggestions below, and let’s see what we can all learn.