Here is my most recent FanGraphs piece. (It made The Best of FanGraphs list for last week!) It revisits the work I did in September on parity between the two leagues. At the time, I noted that the American League, perceived as being weak this year, in fact is overall better than the National League (as measured by interleague won-lost record). I attributed the perception of weakness to the near-record level of parity in the American League, with neither notably strong nor weak years. As measured by the standard deviation of wins, in fact, the American League in 2015 had, at the time, the highest level of parity in the 30-team (since 1998) era.
With the regular season in the books, there are two conclusions. First, parity in the American League didn't turn out to be the highest of the 30-team era. It was the highest of all time. Here is a list of the standard deviation of wins, i.e., the "plus or minus x" amount in the phrase, "The average team had 81 wins, plus or minus x." Here's a list of the ten seasons with the lowest standard deviation of wins since 1901:
The American League this season was the most equal league in major league history.
Despite that parity, the American League clearly was the superior league, for the twelfth straight season:
As with every season, there have been storylines that are unique to the 2015 baseball season. The remarkable infusion of young talent to the game. The relevance of the Cubs and Astros after years of being doormats. The disarray in Boston and Detroit. And, of interest here, the general ineptitude of the American League.
I analyze this supposed AL inferiority in this article on FanGraphs, and this one in Banished to the Pen. The FanGraphs article has data through games of September 5, while the Banished to the Pen piece is through September 9. The conclusion of each is the same:
The record level of parity in the American League to date has smoothed out the top and bottom of the league, resulting in hardly any notably bad or notably good teams. But that parity shouldn’t be mistaken for weakness. The American League is the better league overall, as evidenced by its clearly superior record in interleague play. The National League may have the best teams, but the American League remains the better league.
Over the weekend there was an article in the weekend Wall Street Journal (may be behind a paywall) pointing out that the American League has prevailed in interleague games for ten straight years and appears certain to do so this year as well. In seeking to explain it, the Journal points to the designated hitter:
Because of the DH, AL teams can more easily acquire offensive-minded players without worrying about their negative impact on defense.
That's true, but let me add a couple other factors. First, the presence of a DH allows American League teams to sign long-term contracts to free agent hitters who, by the time their contract expires, probably won't be suited to play in the field. Albert Pujols is the Angels' first baseman. He is 34 and under contract through 2021. Prince Fielder, until a season-ending injury, was the Rangers' first baseman. He is 30 and under contract through 2020. Do you think Albert Pujols will be a first baseman when he's 41, or Prince Fielder when he's 36, especially since both players have battled injuries in recent years? Or consider the past winter's marquee free agent, Robinson Cano. He's 31 and plays second for the Mariners. Plays it well, I might add--he ranks highly in both traditional and advanced fielding metrics. But he's also signed through 2023, when he'll be 40. Doesn't it seem likely that by then he'll be at least a part-time DH by then? National League teams can't sign batters to those kind of contracts, because by the end of the contract, there won't be anywhere on the field to play them. Fine with us, fans of National League teams might say, given that paying Pujols $30 million in 2021, or Fielder $24 million in 2020, or Cano $24 million in 2023, is likely a money-losing proposition in terms of return on investment. But in avoiding those high-cost out years, National League teams are missing out on the near-term years when the players are good. That tilts the balance of power to the American League.
Here's another, mundane reason: The average American League payroll is $109.8 million. The average National League payroll is $104.9 million. (Both figures from baseball-reference.com) Might it be that the American League is better because they pay more and therefore get better players? And before you can say "Red Sox and Yankees," if you exclude those two teams from the AL totals and the Dodgers from the NL, American League teams still have a higher average payroll, $98.9 million to $97.2 million.
