What Run Differential Says About the Orioles

2012 OriolesIf you’re an Orioles fan, you’re probably already familiar with run differential, and statistical anomalies with respect to run differential. The 2012 playoff team had a run differential of just +7, which estimated a far more pedestrian record than the 93-69 record that the team actually pulled together.

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According to FanGraphs, it’s at the 40-game mark that run differential that run differential begins to strongly resemble final record. The Orioles have very nearly reached that point, having played 38 games, so it’s worth opening a serious discussion about the ability of Baltimore’s baseball team to again outperform its run differential. In 2014, the Orioles appear headed in the same direction: a 20-18 record is accompanied by a -10 run differential, which predicts a losing record of 18-20. This season, the Orioles have won by an average margin of 2.65 runs while losing by an average of 5.5 runs. Like 2012, this team has so far won by a far slimmer margin than it has lost. That makes sense: many Orioles fans have observed the feast-or-famine lineup and what now looks to be a similar boom-or-bust pitching staff.

Tommy Hunter

Yeah.

There are a few ways to look at this. First, we can brace ourselves for the wheels falling off. If run differential is stabilizing to show a pythagorean win expectancy of less than .500 ball, we can assume that the luck will run out and the Orioles will lose more than they win from here forward. They’ll end the season with 79-81 wins, just like the books predicted. The bullpen1 isn’t exactly instilling confidence that it can hang on to close games the way it did in 2012, which does not bode well for a team hoping to beat its run differential for a long time.

Second, we can be pedantic about how we discuss run differential: the Orioles are not outperforming their run differential. Rather, they have, to date, outperformed their run differential. The difference there is subtle but important. In one, we implicitly predict a season like 2012, in which the team wins a crazy number of close games and otherwise gets blown out. In the other, we recognize that the team has gotten lucky over its first 38 games, but at the same time treat the remaining 124 games as a clean slate. Starting now, the Orioles have a run differential of 0 and a 0-0 record. To paraphrase Jonah Keri in his early-season editions of The 30, those games all count and can’t be taken away from the team, but it’s advisable to estimate the rest of the season to reflect team quality and not recorded results. If you thought the Orioles were a .500 team, you’d figure the next 124 games to be .500 ball and add that to the current over-.500 record. Most fans predicted this team to be better than .500. Can we throw run differential out the window, bank our wins, and hope to be better the rest of the way than we have been so far?

Chris DavisTypically, this is the sort of thinking is reserved for the small samples of over- (or under-) performance that always happen to start the season. There’s reason to believe that the Orioles and their fans could stick with this train of thought, though. No, it’s not that there are still 2 games to go until the 4-game mark. It’s that, as many fans have lamented, the projected starting lineup from before the season has not yet taken the field. First Manny, then Davis, and now Wieters have spent time on the DL. Certainly it would be foolish to expect the Orioles to perform with Chris Davis manning first base, and more importantly one of the spots in the middle of the lineup, at the same rate that they performed with Markakis and Pearce at first. The same can be said for Manny at third. The real Orioles haven’t played one game together, much less 40.

Let’s assume the worst for Wieters and that he gets Tommy John surgery, ending his season. The complete 2014 roster only started playing together on Sunday, May 11. Since Davis’ return, they’ve had four full games together. Okay, so those four games were all losses. There’s still another 36 before we can resign to let run differential decide our fate. Or, if we take a cue from 2012, we never have to let that define us.


1. Whenever people refer to “problems in the bullpen,” they really mean, “the closer sucks.” I’m good with O’Day and Britton and plenty of other people pitching in relief. I’m talking about Tommy Hunter.

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About the author


Patrick Dougherty  

Orioles Analyst

Patrick is the co-founder of Observational Studies, a blog focused on the analysis and economics of professional sports. The native of Carroll County graduated with a Bachelor’s degree in Economics from Loyola University Maryland. Patrick works at a regional economic development and marketing firm in Baltimore, and in his free time plays lacrosse.


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