THE BOOK--Playing The Percentages In Baseball

Friday, October 21, 2011

Performance in tied games

Note: You may feel you are walking in the middle of a conversation.  You can take a step back and go here.

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Ok, given that we accept that there are pecularities with the 9th inning, bottom half, tied game scenario (unintentional-intentional walks; fielders de-aligned from norm to either defend against the bunt, to guard the line, or to play the OF shallow), I’m now going to focus only on the tied-game scenarios for all innings.

So, here’s the A_empty group (as a reminder, all bases empty situations, regardless of outs), for tied games, broken down by inning (1st, 2nd thru 8th, 9th, extra innings):

First 4 lines is top of inning, and next 4 is bottom. 

Our “control” group is basically innings 2 thru 8.  As we can see, at home, you get a 12 point advantage in OBP, 10 point advantage in BABIP, and since wBABIP=BABIP that means the rate of extra base hits per in-play hit remains constant (i.e., excludes HR). 

wBABIP is BABIP but with extra weight placed on extra base hits and less weight placed on singles.

As we saw in the other thread, the massive difference in OBP in the 9th inning is explained by the walk rate and singles rate.  The extra innings carries this issue as well.  So, any analysis of tied games in the 9th inning has to be able to handle these parameters, otherwise you are going to introduce a bias.

The interesting one though is the 1st inning.  We ALSO see a massive gap in the 1st inning, with a 27 OBP point gap at home than on the road.  As we said, 12 points of that is the home field advantage.  The K and BB rates are simply hugely different, as it plummets to 14.5% K rate in the bottom half (compared to 17.3% in the top half) and jumps to 10.0% in BB+HB rate in the bottom (compared to 8.7% in the top).  It might be clearer to see it as a K to BB+HB ratio: 2.00 in the top half and only 1.45 in the bottom half.

My original speculation was that the road pitcher, being the second pitcher to take the mound, simply hasn’t found his mound groove.  I wish I would have included one other parameter in my dataset (which I can do on the weekend): handedness of pitcher.  If both pitchers are right-handed, they may “compete” for the mound groove.  If they were opposite-handed, then it might make it easier for each to take their own side.  Just a thought, one that I will also leave with the PITCHf/x-ers.  Anyway, someone asked about day/night splits maybe.  So, let’s see.

Here are the splits by day:

The control group (innings 2 thru 8) shows a 14 point home advantage for OBP and a 8 point advantage in BABIP.  There’s no extra base hit advantage.

Innings 9 and extra innings shows the same massive gap, as explained earlier. 

Inning 1 shows a 29 point OBP advantage at home, and 16 point advantage on BABIP, numbers that are a bit bigger than overall.

Here it is at night:

The gap is somewhat smaller at night in terms of home advantage.  The control group shows a 11 point OBP advantage and 8 point BABIP advantage.  The first inning shows a 26 point OBP advantage and 13 point BABIP advantage.

Across the board, the day time advantage is an extra 3 points in OBP.  I would not be surprised that if you look at historical home/away splits, that the day splits show a slightly higher home advantage.

Anyway, let me now focus on the B_2out grouping (all PA with runners on base and 2 outs).  Maybe by this point, the mound familiarity starts to come into focus (and maybe not using the windup helps too in combating the mound effect).

Control group shows a 14 point OBP advantage and 3 point BABIP advantage at home.  The first inning effect shows only an 18 point OBP advantage at home, but 13 point BABIP advantage.  The OBP gap between 1st inning and control group is no longer very wide.

I think the next thing to look at is simply by 1st, 2nd, 3rd batter in the game.  I’d bet we’ll see a huge gap in OBP when comparing the 1st batter’s first plate appearance in games at home and on the road.  And then a progressively smaller gap for the 2nd batter faced in the game, and 3rd batter.  And that by some point, maybe the 2nd inning, the gap remains static.

If it’s not due to the mound, then perhaps this effect is that the road pitcher has to sit around waiting to pitch in the 1st inning.  The home pitcher gets to pitch right away after his mound session.  Maybe the solution is that the road pitcher should warm up during the top of the 1st inning even?