Tuesday, June 19, 2007

A Sabermetric Detour

I should have run these numbers a month ago. I kept noticing that the Yankees overall numbers, particularly their Runs Scored, were not bad, and kept telling myself they were probably "a little better" than their record. As a Red Sox fan, I regarded Boston's barrage of wins as their just due, even though the Runs Scored versus Runs Against were a little weaker than expected.

There is a sabermetric formula called Pythagorean Wins. Developed (unsurprisingly) by Bill James, it predicts a team's winning percentage on the basis of runs scored versus runs allowed. Over the course of a season, the anomalies balance out and it reflects the number of actual games won pretty accurately. A more complicated version of the formula is more accurate still, but is unnecessary for our purposes here.

Its best use is to look at a team's winning percentage versus its expected percentage (according to RS v. RA) to see if there is any large discrepancy. Large discrepancies usually mean that a team's luck is temporarily out of whack, and one can look for that to even out. One month ago, the Yankees were much better than their record suggested, the Red Sox slightly worse. That is now evening out.

According to the Pythagorean Wins formula, the standings in the American League East should be:

Boston .614
NYY .604
Toronto .511
Baltimore .479
Tampa Bay .395

The reality is
Boston .638 (meaning that they've been a bit lucky)
NYY .522 (meaning they've been very unlucky)
Toronto .478 (a little unlucky)
Tampa Bay .456 (quite lucky)
Baltimore .420 (quite unlucky)

The most logical prediction, therefore, is that the gap between the Red Sox and Yankees will close further. Dogfight again.

Also, look for Baltimore to move up as the season progresses and Tampa Bay to move down. There is a major caveat here, however. Tampa Bay is loaded with young players who are improving every month. The rule of thumb is that baseball players peak between ages 26-28, decline slowly for a few years, then fall off the cliff before age 35. For pitchers, only slightly older. Players who are 23 or younger who have already made it to the major leagues, therefore, improve enormously as a group over their next five years. Given that there are still managers with an uncanny ability to screw up young pitchers, the group improvement is even more impressive.

The name Hanley Ramirez may trouble Red Sox fans as an illustration here.

Tampa Bay has more players in this category than any other team, and so may improve consistently over the course of the season, negating their expected fall in luck. A hurried look at the TB lineup would suggest that they are going to be a force in 2008 and 2009. The Devil Rays, however, have a remarkable record of throwing away or screwing up talent. Keep your eyes on these guys, though:

Delmon Young 21. RF, fair-good, and improving month by month
BJ Upton 22. 2B - already has an OPS of .941
Scott Kazmir 23. SP, ERA 4.10
Elijah Dukes 22. CF, hits lefties well but poor against righthanders.

Plus James Shields and Carl Crawford, both 25.

3 comments:

Michael said...

For those who can't do the math, MLB.com now includes "X W-L" as a standings option on their website. A quick look at today's standings show the Chicago Cubs having the same -5 wins as the Yankees as are the SF Giants. The luckiest team in the majors to date? The Arizona Diamondbacks,(+5) who, because of that "luck" are challenging the San Diego Padres for the lead in the NL West.

An interesting correlation appears. The Yankees are 4-10 in one run games, the Cubs are 7-14 and the Diamondbacks are 17-8. Throw in the Giants 9-13 and it seems as if record in 1 run games is a pretty good indicator of this stat.

As for the Devil Rays, while all the players you mention are potential stars, I agree with you that in their history, the Devil Rays don't seem to be able to put it all together. But if they do, they should be capable of challenging the Yankee/Red Sox lock on the division in the foreseeable future. And while not all that young any more, Carlos Pena, a castoff of the Tigers and Red Sox (and a Massachusetts boy, no less) is tied for 6th in the majors in the HR category this season. His SLP, if he had enough AB, would put him just behind ARod and just ahead of Magglio Ordonez. That's second place. So, AVI, you are perceptive as usual.

Assistant Village Idiot said...

Wouldn't you know there's an easily-available simple version so I didn't have to do it by hand. I follow all my sports on ESPN's site, which doesn't have that, I don't think.

One-run games are another false impression phenomenon. When you are watching a game, a team's ability to win close games is exciting, and we attribute all sorts of baseball virtue to teams that do it. But a moment's thought and a slap on the head will remind you that a team that wins its games 8-3 is better than one that wins them 4-3. Baseball being what it is, with bad strike calls, bleeder singles, and wind conditions, it has a lot of luck in any individual game. That's why they play so many, to even it out. Winning lots of close games might indeed be a measure that your team is on borrowed time.

There are teams which win more one-run games than expected year after year, and that does suggest that they do something different: fewer errors, ability to switch to small ball, I don't know.

I am going to guess that the number of 0ne-run games you should win is about halfway between your winning percentage in your other games and .500.

Giacomo said...

On the other hand, as a Red Sox fan, I could certainly argue that the Sox are somewhat below what should be their pre-season predicted run-scoring ability, with the slow starts of four of their starting nine (Ramirez, Crisp, Drew, Lugo) Over the course of a season things tend to revert to form, and we may be seeing that already with the increased production of Crisp and Ramirez of late, and Drew's improvement as the leadoff hitter.

I do agree that the Yankees were due for a run (nine in a row, eh?) and will have some other runs.