Tuesday, September 21, 2010
When is a non-intentional walk intentional?
There are two walks to think of walks: in terms of their run-producing impact, and in terms of their win-producing impact. Lee Panas brings up the case of Miguel Cabrera who has 55 unintentional walks and 30 intentional walks. You can likely find in MLB history some equivalent player with 85 walks, but only 5 or 10 of them being intentional, and at the same time, both players having equal win-producing impact on those walks.
If you IBB a player with 1B open, 2 outs, and up by 1 run, the run and win impact is the same as a regular walk. Indeed, what the IBB is saying is basically: “Take MOST of the walks issued with 1B open, 2 outs, and a close game, and call those IBB”. Not exactly, but disproportionately so. Given that we know the game state of every walk issued in the last 60 years, we come to the point that we don’t necessarily need to distinguish between an IBB and NIBB: we just classify them based on their win-impact.
Hence, WPA/LI or RE24/boLI. What do those numbers mean? You take the win or run impact and divide it by the leverage of the situation. That puts it on a neutralish scale. What you will find is that those walks classified as IBB will have a win impact under +.010 wins and a run impact of +.180 runs (more or less, using standard win and run charts). For non-IBB, some of them would give you +.010 wins, and therefore, may as well have been called IBB.
Heck, you can do the same thing for a batter’s unintentional strikeout: any time a batter strikes out with a runner on 3B and less than 2 outs, classify that one differently, since its run impact is disproportionate from the other base/out situations, and we know the batter (and pitcher) is approaching that PA differently.
In the end, you just end up on a path to RE24 (or preferably RE24/boLI, or most preferably WPA/LI).


RE24/boLI and WPA/LI still don’t account for the value lost from Pujols batting vs. the next guy in the lineup. The problem I have is if we did try to take this into account, we’d end up penalizing Pujols for being a better hitter than the guy behind him in the lineup which seems unfair.