Juicing the bases early

Recently, MGL posted an article about intentional walks early in baseball games, and Peter Jensen followed-up with an article on TangoTiger's site. I read Peter's article and decided to try similar things, with a larger sample and more granular data. I have never really tried to do this kind of analysis before, so I hope I don't make a fool of myself.

In any case, I won't go over too much of the details because you can read Peter's article here and follow-up comments here.

I am using a very similar methodology to what Peter used, with a few changes:

1) I am using data from 2000-2007.

2) I am only counting walks that are "obvious" IBB's. That is, the result of four consecutive intentional balls.

3) I am only looking at PA's where the batter is in the top 6 spots of the order. This does two things for me. First, it controls a little bit for the quality of the batter, and second, it allows me to incorporate National League data which increases my sample size. I am, however, throwing out Barry Bonds PA's because, well, because.

4) Instead of breaking it up into two "groups," I am seperating the events by the score.

All in all, I identified 6094 PA's between 2000-2007 with runners on second and third, one out, prior to the 7th inning in completed games, where the batter was in the top-six spots of the order. In 564 of the cases, an "obvious" intentional walk was issued.

Here are the oIBB counts, broken down by the relative score from the vantage point of the pitching team:

Score Diff	N	oIBB	N%	oIBB%
Tied	1485	129	8.69	22.87
-2	720	99	13.75	17.55
-1	1030	97	9.42	17.20
-3	472	88	18.64	15.60
-4	288	39	13.54	6.91
+1	625	39	6.24	6.91
-5	166	28	16.87	4.96
-6	104	17	16.35	3.01
+2	417	14	3.36	2.48
-7	61	6	9.84	1.06
-8	29	5	17.24	0.89
-10	15	1	6.67	0.18
-9	21	1	4.76	0.18
+4	155	1	0.65	0.18

Like Peter, I didn't find any cases where an IBB was issued with a 3 run lead, but Lloyd McClendon did issue one with a 4 run lead in this game.

From here, I looked at out how often teams won and lost when they issued an intentional walk versus when they "pitched away." I will go through one example to explain the data and then simply post the table. In 1485 of the 6094 overall instances, the game was tied. Managers issued an obvious intentional walk 129 times, or 8.69% of the time. In the games where they issued an oIBB, they went 46-83, for a 0.357 Wpct. In the games where they did not issue four straight intentional balls, they went 514-842, for a .379 Wpct. So the difference between the two is 0.022 in favor of not issuing the walk. This translates to 2.9 wins lost over the 129 games where the walks were issued.

Here is the table for all situations that had a decent amount of oIBB's. The "IBB Gain" is the amount of wins the team "gained" by issuing the walk, based on the difference in percentage. Obviously a negative number means wins were lost.

Score Diff	No-IBB Record	IBB Record	No-IBB W%	IBB W%	Diff	IBB Gain
Tie Game	514-842	46-83	0.379	0.357	-0.022	-2.898
-2	117-504	16-83	0.188	0.162	-0.027	-2.652
-1	260-673	31-66	0.279	0.320	+0.041	+3.969
-3	48-336	7-81	0.125	0.080	-0.045	-4.000
-4	13-236	2-37	0.052	0.051	-0.001	-0.036
+1	284-302	20-19	0.485	0.513	+0.028	+1.099
-5	6-132	0-28	0.043	0.000	-0.043	-1.217

I am not sure how to assess the "significance" of these numbers, so I will leave that to someone else, but obviously what sticks out is that number down by a run. When trailing by a run in the early innings and with runners on second and third, one out, and a "heart of the order" guy at the plate, teams did 4 wins better when they intentionally walked that batter. In almost all the other situations, issuing the walk cost the team wins. I am thinking about re-running the numbers with a larger sample to draw better conclusions, but at first I thought I'd let you guys criticise the methodology.

So go ahead! :-)