This (so far) American Century
I remember a year or two ago, there were a bunch of really exciting young pitchers in the National League and one might have entertained notions about the National League finally ending the American League's long run of hegemony.
Uh, not so much, it turns out. As Jeff Sullivan points out, once again the A.L.'s killing the N.L. in every imaginable way for essentially the 13th straight year.
Some points of possible interest: this year, the average AL team had an opening-day payroll a little under $2 million higher than the average NL team. Last year, the average NL team was higher by a bit more than $2 million. But in truth, this doesn’t mean anything if you don’t take service time into account.
And then, pulling from Man Games Lost, this year the average NL team has lost 776 games to injury. The average AL team has lost 676, exactly 100 fewer. But right now we don’t have a good measure of how important those missing games have been. It’s a partial explanation for the discrepancy in success. I’m skeptical it’s a big one.
--snip--
In closing, if you want a neat little way to think about this, we can make use of the Log5 equation. Let’s take just this year’s AL interleague winning percentage. If you think that reflects real ability, then the AL would be a “true talent” .525 league, and the NL would be .475. So the average interleague game would be like an 85-win team playing a 77-win team. Let’s now say, instead, you believe more in the Pythagorean record. Then it’s more like an 87-win team playing a 75-win team.
The observed qualitative difference between the leagues hasn't always been so dramatic, but throughout this 13-year run it's usually been significant. These 13 years cannot simply be passed off as random fluctuation.
So what's behind it? Jeff mentions two potential lines of inquiry, but the A.L.'s spending advantage is obviously small, and the games lost to injury, while seemingly significant, tells us nothing about the phenomenon before 2015.
What I think, in fact what I've always thought, is that the American League teams are just a little smarter than the National League teams, largely because the Yankees (with their money) and the Red Sox (with their big brains) dragged the competition along with them.
Not a lot smarter. But it wouldn't take a lot. If you were just 3 percent smarter when drafting and 3 percent smarter when signing free agents and 3 percent smarter when tutoring your pitchers and 3 percent smarter when hiring doctors and physical therapists and ... well, all those 3 percents would add up. Shoot, a bunch of 1 percents and 2 percents would add up.
So that's my best guess. Because no, it's not about the DH.