Monday, September 28, 2009
Debunking the debunker
Posted by Colin WyersFrom Rays Index:
How many times have you seen it written or heard somebody say:
“Wins is a useless way to evaluate a starting pitcher”
Apparently at least one time less than it needs to be said.
The thrust of the post:
What we see is a very clear trend. As a pitcher’s ERA+ goes up (bigger values are better, 100 is average), their win total goes up. Are there exceptions? Of course. Every statistic has exceptions. But even in the face of contradictions, we still see a very strong correlation (r-squared = 0.51).
Um. Sure. Pitchers who have a better ERA tend to win more games. (Shocking, I know!)
But so what? I mean, it's great that we have a statistical measure that can tell us Zack Greinke has been one of the ten-best pitchers in baseball this season. I guess. He's sixth, three wins behind leader Adam Wainwright. Now, of course Wainwright has walked more batters, struck out fewer batters and given up more home runs than Grienke (and, for those worried about it, given up more earned runs as well) in spite of the fact that he gets to face a pitcher hitting in lieu of the DH for most of his games.
So how does Wainwright win more games than Greinke? Run support. The Cardinals have scored 5.51 runs per game while Wainwright is on the mound; the Royals have scored only 3.77 runs per game when Greinke pitches.
In other words, wins are a great stat for evaluating pitching, if you think that having Albert Pujols as your first baseman instead of Billy Butler is an important aspect of a pitcher's performance. You can of course continue to use wins if you don't need a pitching stat accurate enough to tell you that Carlos Zambrano has pitched better than Braden Looper this year.
In short, pitcher wins tend to work well in groups (if you look only at pitchers who qualify for end-of-season awards, yeah, the group of 15-win pitchers on the whole is going to be better than the group of 10-win pitchers). But they can be highly misleading if you want to use them to compare two individual players.
And for the kicker:
The problem with this post, is that taking a pro-Wins stance leads some to believe that we are anti-other stats. That couldn’t be further from the truth. Stats like ERA+, FIP and tRA are still better measures of how good a pitcher is (although we have minor quibbles with each). However, that does not mean Wins is a useless category. Nor does it mean there are 95 better ways to evaluate a pitcher.
In fact, in the absence of other stats, Wins is a very good, if not great, indicator of a pitcher’s value. So next time you hear somebody say Wins is a crappy way to evaluate a pitcher, throw a drink in their face and then make them read this post.
(Emphasis mine.)
But there isn't an absence of other stats! Here, let me help you out:
There. Now you never have to worry about having no other pitching stats except for wins ever again. Problem solved.
Again, to review:
- Never use wins to determine a pitcher's value, relative to other pitchers.
- Ever.
- I mean EVER.
Colin Wyers knows exactly how much of a nerd he is. He is very interested in hearing about any other concerns you may have; you can reach him by e-mail, and he will try his best to respond in a timely fashion. He also blogs at Statistically Speaking.
Well said.
I laughed when they said “As a pitcher’s ERA+ goes up ...their win total goes up” & used it as proof that win totals must show how good the pitchers performance was. In that same sentence, they just used ERA+ AS THE REASON why a pitcher’s win totals are good and claim win totals are an accurate measure! I’d like to hear them explain the win totals & ERA+‘s of Curt Schilling’s 2003 or Ben Sheets’s 2004 seasons. I’m sure that’d make for some laughs too.