2005's "true" White Sox and Indians

In 2005, the Chicago White Sox won the Central Division and the World Series. The Cleveland Indians failed to even make the playoffs. But were the Indians the better team?

At face value, the answer is no. Baseball is about winning games and eventually winning championships. The White Sox won more games than the Indians, and won the championship. They were the better team.

However, available evidence indicates that baseball teams have the ability to score runs and prevent runs; they do not have the ability to win games. Winning (and losing) stems from scoring and preventing runs---no team inherently possesses the ability to win close games (I'm sure I will be receiving a counter-argument from Ozzie Guillen any day now...).

The "Pythagorean theorem of baseball" (so named because it contains several squared terms) predicts a team's wins and losses based on its runs scored and runs allowed. There are deviations from this predicted record, but the theorem remains true on a large scale, and all available evidence indicates that there are no factors other than luck that cause a team to under-perform or over-perform their projected record.

In 2005, the White Sox scored 741 runs and allowed 645. The Indians scored 790 and allowed 642. That's right: the Indians were better at scoring runs, and the two teams were basically even at preventing runs. The White Sox's Pythagorean projected record was 91-71; the Indians' was 96-66.

But wait, there's more. Sometimes actual runs scored and runs allowed are not indicative of a team's ability to score or prevent runs. For example, some teams hit an unluckily high amount of solo home runs based on how many base runners the team had. This results in a lower amount of runs scored than normal. Also, sometimes pitchers can be lucky or unlucky in a similar way.

Baseball Prospectus accounts for these other elements of luck with "Third Order Pythagorean" standings. Once these adjustments are made, here are the projected 2005 standings:

Chicago White Sox 87-75
Cleveland Indians 98-64

Basically, in 2005 the White Sox were incredibly lucky, and the Indians were unlucky.

What does this mean? Obviously, it changes absolutely nothing for 2005---the White Sox are still World Champions, and the Indians still failed to make the playoffs.

What it does change is 2006 projections. Statistical variation (luck) tends to regress to the mean. If you are particularly lucky one season, chances are you will not be as lucky next year. The White Sox's 99 wins (and the Indians' 93 wins) did not represent the true of abilities of their 2005 teams. In other words, if you play the season over again, with the same players producing the same results, Chicago will not be as lucky, and Cleveland will not be as unlucky. The 2005 Indians had a true ability of 98 wins, not 93 wins. The 2005 White Sox had a true ability of 87 wins, not 99 wins.

As I said, this changes nothing for 2005, but does alter projections for 2006. Because the White Sox's "true" ability was 87 wins in 2005, 87 should be the base from which we judge improvements or downgrades. Furthermore, the Indians' base should be 98 wins.

The 2005 White Sox were baseball luckiest team. This luck will not continue.