Team-Adjusted Wins

Last year, Felix Hernandez went 13-12 for the Seattle Mariners while C.C. Sabathia went 21-7 for the New York Yankees, David Price went 19-6 for the Tampa Bay Rays, and Jon Lester went 19-9 for the Boston Red Sox. King Felix won the Cy Young Award, however, largely because his 2.27 ERA and 249.2 innings pitched were both miles better than the corresponding numbers put up by the other three pitchers (3.18/237.2, 2.72/208.2, and 3.25/208.0, respectively). Some persons complained about this, arguing that while ERA, innings pitched, and the Wins Above Replacement metric largely derived from those two figures are nice, having an essentially .500 won-loss record just isn't okay for the pitcher anointed as best in the league. Well, here's a way to synthesize these two concerns: team-adjusted wins.

(Note: credit for this idea belongs entirely to my father.)

Suppose we ask of a pitcher not, how many games did you win and how many did you lose, but rather, how much better did you do at winning games than your team as a whole? Let's quantify this: how does your won-loss record compare to that of a pitcher with the same number of decisions but a winning percentage equal to that of your team as a whole? Now if we look at these 2010 AL Cy Young contenders, we see the following. Felix Hernandez' Mariners lost 101 games, and if King Felix had lost games at that same pace he'd've had a record of 9.4 wins and 15.6 losses; compared to this, he added about 3.6 wins. Sabathia's Yankees won 95 games, and at that pace C.C. would've been 16.4 and 11.6, so he added about 4.6 wins. Price's Rays won 96 games, which would've made him 14.8 and 10.2, so he added around 4.2 wins. Lester's Red Sox won 89 games, at which pace he would have had 15.4 wins against 12.6 losses, giving him 3.6 wins added. King Felix is still more or less last, but not by the same kind of margin that 13-12 versus 21-7 looks.

Let's make this calculus even more sophisticated, though. It doesn't really make sense to use a team's overall record as the baseline we're adjusting to because, after all, that record includes all of the games that the pitcher we're trying to evaluate participated in deciding. Instead let's adjust a pitcher's record to their team's performance in games decided by other pitchers. Now we find that Hernandez would've had 8.76 wins in his 25 decisions, Sabathia would've had 15.46 wins in 28 decisions, Price would've had 14.05 wins in 25 decisions, and Lester would've had 14.63 wins in 28 decisions. So Sabathia still leads the pack with 5.54 adjusted net wins, followed by Price at 4.95 adjusted net wins, Lester at 4.37 adjusted net wins, and Felix at 4.24 adjusted net wins. It's the same story: Hernandez is a little behind these other guys, but just barely.

We can also get a better visualization of these numbers by projecting what each pitcher's record would've looked like if they played for a .500 team. Rounding to the nearest integer, I project Hernandez at 17-8, Sabathia at 20-8, Price at 17-8, and Lester at 18-10 (though Sabathia just barely manages to round up, and Price just barely misses doing so). If those had been these pitchers' records, and Hernandez led the league in both ERA and innings pitched, would anyone have batted an eye at his being awarded the Cy Young? I don't think so. Perhaps some people would make the same generic complaint about giving the award to someone who played on a bad team. That's a different kind of argument, though, arguing that his accomplishments shouldn't be valued as highly instead of arguing that his accomplishments weren't actually that impressive in and of themselves.

Obviously this stat doesn't capture everything, most notably the fact that different pitchers do receive different levels of run support, possibly more or less at random. For instance, in 2010 Felix Hernandez received just 3.1 runs per game from his offense, about normal for the extremely anemic Seattle team, while Sabathia had 5.9 runs per game, well above the 5.3 runs the Yankees cranked out over the whole season. The fact that Sabathia not only played on a good team but got above-average support from that slugging lineup, while Hernandez received only average production from his awful offense, might make up some of the difference between their records that remains after making this adjustment. However, the notion of wins and losses remain integral to some people's notions of what a starting pitcher in particular should be judged by, and adjusting for a team's overall performance is a good way to make a pitcher's record a more reliable indicator of their performance.