We have fallen down quite a rabbit hole in examining Joe Girardi and his use of the intentional walk. Raw totals turned into a puzzling simple data point which turned into further head scratching via an examination of context. Today, we pick up where we left off and ask the question of whether or not Joe Girardi’s intentional walks are adding value to the team.

We left off wondering aloud whether putting men on base when there were already men on base was silly. After all, is the perceived value of a matchup strong enough to override the chance of more runs scoring because there are more people on the basepaths? There are a number of ways to answer this question. For the sake of simplicity, we will use an established metric: Win Probability Added (WPA). If you are unfamiliar with the term, here is the definition from Fangraphs:

“WPA is the difference in win expectancy (WE) between the start of the play and the end of the play.”

As the definition implies, WPA assesses the increased / decreased probability of a win depending on the score, outs, and bases occupied. You can find a real world example of WPA by clicking the above Fangraphs link. Just to be clear, issuing an intentional walk will nearly always result in a lower WPA for a team because there is now another dude on the base paths that can potentially score and impact the game’s outcome. What we are trying to isolate is whether or not Girardi’s decisions to intentionally walk batters are more damaging to the team’s winning potential than his peers. WPA provides us a somewhat quick and dirty metric for addressing this question. In order to draw an effective comparison that incorporates the volume of a team’s intentional walks, we will divide the WPA accrued by each manager on IBBs by the number of IBBs issued to come up with a crude “WPA rate.” This will allow us to assess the impact of the decision on the game’s outcome and render a judgment on Girardi.

So, for the period from 2008 to 2012, how did The Binder do relative to his peers in the WPA rate category? The Yankees, for that time, period clocked in with the fourth worst WPA rate in the American League (tied with the Blue Jays). In practical terms, according to WPA, while a Joe Girardi intentional walk may have saved a run here or there, in aggregate, his decisions to issue base on balls are lowering the Yankees win potential at a higher rate than the majority of the American League.

That’s obviously not something to be proud of. In essence, his decision making on these intentional walks is questionable. How else can we back this up? Deep in the bowels of the Excel Cave (this is like the MLB Fan Cave, but somehow even sadder), something became clear: there is only a somewhat distinct correlation between the number of intentional walks issued and the negative magnitude of a team’s WPA. For the period from 2008 to 2012 the correlation checks in at 0.72 so it’s not “automatic” that issuing more intentional walks results in a lower win probability. However, this does illuminate two things:

1.) Because intentional walks aren’t always bad according to WPA, but The Binder is accruing more negative WPA when he orders four wide ones, we can more safely say that he demonstrates poor judgment when making the decision to intentionally walk a hitter and that the “over managing” moniker is more deserved.

2.) The correlation between negative magnitude of WPA and the number of intentional walks issued is high enough to beg the question of whether or not managers rely on IBBs too much in general. While IBBs are not as damaging as surrendering home runs (obviously), it‘s hard to ignore the fact that issuing more of them tends to decrease the win probability of a team.

At the very least, we can use the above as a reason to freak out when The Binder walks more and more people, right? Right!

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