Leadoff Walks

During last nights Jays/A's game, BJ Ryan came into the ninth inning to close out the one-run lead, and immediately issued a lead-off walk to Mark Ellis. I hate leadoff walks, and so does Rance Muliniks. In fact, Rance remarked (paraphrasing):

"I would estimate that the leadoff walk comes around to score 60-65% of the time."

I generally like Muliniks, but whenever a broadcaster makes a claim like this, something triggers in my brain. Rance went on to give reasons why he thinks walks come around to score so often, but I wasn't listening.

In The Book, the authors present a table of run values for all the batting events by base/out state. The unintentional walk, with the bases empty and no outs, has a run value of 0.41, so that doesn't help Rance's case. Not ever someone to take someone on their word, I ran the numbers myself, using data from 1998-2007. Here's what I found:

BBs     R       %
-------------------------
27929   10797   .3865

So in 27,929 leadoff walks, the runner came around to score about 39% of the time. Pretty close to the value from the book, and not nearly as high as 65%.

But that's not really the issue. The assertion, see, is that leadoff walks are "special." That is, the runner is going to score more often after being walked than he would had he singled (or reached first some other way.) That's easy to check.

Let's see what the numbers are for leadoff singles:

1Bs     R       %
-------------------------
62645   24031   .3836

Oh. 38%. Basically the same. Drat.

Sorry, Rancey baby.