In MLB, Sometimes It’s Better To Be Lucky Than Good

Now that we’re coming down the stretch in the 2010 MLB season, it’s becoming increasingly clear which teams will and will not be headed to the playoffs. Teams like San Diego and Cincinnati, whom no one expected to do anything meaningful, both have excellent chances of playing in October, while heavily-hyped teams like Colorado and Boston could find themselves staying home. Sometimes it’s tough to separate the teams that are genuinely better than people expected from those that are simply lucky.

Fortunately, we’re here to help.

Baseball, perhaps more than any other sport, has a high correlation between winning and margin of victory. Obviously, you tend to win when you score more than your opponents do, but in baseball, you when you tend to score much more than your opponents, you tend to rack up a lot of wins. A big part of that has to do with the large sample size found in a baseball season (twice as many as a basketball season and nearly 8 times as many as football), but for whatever reason, it’s a principle that tends to hold true. In fact, a good, if somewhat less than exact, rule is that for every 5 extra runs in your total scoring differential, you tend to be one extra game over .500. For example, a team with a scoring differential of 50 for the season could reasonably expect to find themselves 10 games above .500.

Armed with that knowledge, we can compare a team’s scoring differential to their record to see if we should expect them to be as good (or in some cases, bad) as they are, or if they’ve simply been lucky.

One of those lucky teams this year has been the Chicago White Sox. Left for dead at the All-Star break, the Sox have made a tremendous run and currently find themselves in first place in the AL Central. Their scoring differential (+57) is more or less consistent with their record (14 games over .500), but that’s not what makes them so lucky. It’s the Minnesota Twins, consensus pick to win the division, who have put them in first. The Twins have outscored their opponents by 89 runs this season, yet only find themselves 11 games over .500 and a game and a half behind the Sox. A record consistent with that differential would actually be 63-44, which would not only give them the division lead, but would also give them a record better than any team in the National League.

So whether you want to call the White Sox simply average or the Twins unlucky, it’s clear Chicago is reaping the rewards of luck here.

Meanwhile, the San Diego Padres have been labeled a fluke this year. No one expected them to contend for the NL West crown, and in fact, most picked them to finish behind the woeful Arizona Diamondbacks in last place. However, the Padres have refused to fall back and currently own the best record in the NL (and third best in the entire league, behind only the Yankees and Rays). A quick look at their scoring differential will tell us whether they’ve been good or merely lucky. They’ve outscored their opponents by 96 runs (third best in the league!), which would suggest a record of 62-42. Shockingly, that’s the exact record they’re sitting on right now.

You could argue that they’re only in first because the other teams in the division are underperforming, and there might be something to that. The Rockies are a game worse than their scoring differential would predict. The Giants are two games worse. The Dodgers, however, are overachieving, and they’re still eight games out of first place. It doesn’t hurt to be lucky, certainly, but there’s no denying that the Padres are good.

But what does any of this matter? The teams with the best records still get into the playoffs, so why should we care if they got there by playing well or simply by being lucky? That’s certainly true, but with two more months to go, it’s anything but certain which teams will be playing in October. Teams finding themselves looking up in the standings at lucky clubs might take hope at the thought that the tides could change soon. Then again, those behind truly good clubs might be better off focusing on next year.

Dodgers sportscaster Vin Scully once remarked that he didn’t trust any lead in August. So much can change in the two months between then and the playoffs. He has a point. But it’s probably still worth nothing whether a team built its lead by luck or by skill.