Saturday, June 09, 2007

Quiet Week?

I know I say this every week, but I'm sorry about the lack of posting here. I haven't been completely silent: on Tuesday, my third Prospectus Toolbox article came out, this time dealing with relief pitching stats. Here's a taste:

If saves are such a bad statistic, then what tools should we use to evaluate relievers' performances? When evaluating offense, we tend to emphasize components (hits, walks, home runs, outs made) over results (runs, RBI). That's because we're usually trying to isolate one hitter's performance from those of the batter before him and the batter behind him. The pitcher, on the other hand, stands alone on the mound, and for better or for worse, we tend to blame him for anything that happens in the game while he's up there. The best-known pitching stat, earned run average, is results-oriented: it doesn't matter if a pitcher's earned runs come on solo homers or in a soft barrage of singles and walks, all that matters is how many earned runs have scored. However, ERA isn't the ideal statistic for relievers, either, in large part because relievers often come into the game with another pitcher's runners already on base, and they sometimes leave runners of their own on base for the next reliever on their team to deal with. Any good reliever evaluation stat would have to account for how well the reliever prevents those inherited runs from scoring, and what sort of situation he tends to leave for the next reliever on his team to clean up.

The advanced relief statistics we use here take an extremely result-oriented approach to a relief pitcher's contributions. Using different methodologies, these statistics look at the game situation when the reliever enters the game, and compare that to the game situation when the reliever leaves the game (or the game ends), without much concern over how we got from Point A to Point B. That comparison creates a positive or negative value that represents how well (or poorly) the reliever helped his team by preventing runs from scoring.


If you want to learn more about these advanced stats, you can check out the article here. One piece of research that I did for the article was a look at relief innings against total innings over the years. One side-effect was that I as able to look at the Yanks' relief usage over the last couple of years. It probably won't come as a surprise to anyone, but the Yanks (as of last Monday) had the second-highest percentage of relief innings pitched, 39.2%, a handy boost over 2006's percentage of 35.3%.

Anyway, while I've been occupied with my Baseball Prospectus work, as well as my regular work, the Yanks have been taking care of business. Since the Yanks lost to the White Sox on Monday night--putting a stake through the heart of Matt DeSalvo's Yankee career hopes (he now seems to occupy the same tender place in Torre's heart that's been reserved for Colter Bean)--they've looked like the team we figured would show up at the beginning of the season, alternately grinding opponents into submission and hitting hard in the late innings. Very nice.

We're not calling it a wi...er, we're not calling this anything. More after Rocket Launch.

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