Today we'll run another tidbit from the errata of It Ain't Over 'Til It's Over: The Baseball Prospectus Pennant Race Book...
During which decade did baseball fans enjoy the best pennant races? Bill James, in The New Bill James Historical Abstract says unequivocally that the 1940s was "The Best Decade Ever for Pennant Races". Our compilation of Race Score by decade agrees.
Decade Aggregate Races Avg
1900s 375.5 12 31.3
1910s 234.9 9 26.1
1920s 423.6 12 35.3
1930s 226.1 13 17.4
1940s 390.9 11 35.5
1950s 371.5 12 31.0
1960s 385.1 12 32.1
1970s 310.0 17 18.2
1980s 354.1 20 17.7
1990s 247.0 16 15.4
2000s 431.5 27 16.0
The 1940s pulled out the highest average Race Score although the 1920s came in a close second and actually included one more race. Interestingly, the 1930s included 13 races, the highest percentage at 65% of any decade, and nine of those were in the NL with only 1931 excluded. However, many of the races were only marginal with the 1934 NL race won by the Cardinals on the strength of a 33-12 record down the stretch taking the highest score at 29.9 and ranking 43rd.
James ranks the races of the 1940s and so here is his list alongside our ranking.
James Year Lg Score Rank Teams Winner
1 1940 AL 46.0 16 3 Detroit Tigers (90-64)
2 1944 AL 21.0 80 2 St. Louis Browns (89-65)
3 1948 AL 72.0 3 3 Cleveland Indians (97-58)
4 1946 NL 32.9 35 2 St. Louis Cardinals (98-58)
5 1949 NL 37.0 30 2 Brooklyn Dodgers (97-57)
6 1949 AL 37.0 29 2 New York Yankees (97-57)
7 1942 NL 50.9 15 2 St. Louis Cardinals (106-48)
8 1941 NL 36.5 31 2 Brooklyn Dodgers (100-54)
9 1945 AL 18.0 86 2 Detroit Tigers (88-65)
10 1945 NL 29.9 43 2 Chicago Cubs (98-56)
1947 NL 9.8 2 Brooklyn Dodgers (94-60)
The only race from the 1940s that James doesn't include is the 1947 NL race which ranks 121st on our list in which the Dodgers overcame the Braves at midseason and held off the Cardinals, winning by a margin of five games. As James notes, the NL races of the 1940s were dominated by the Dodgers and Cardinals while in the AL the races were more diverse.
This compilation by decade also reinforces the notion that modern races garner lower race scores overall as not only the average Race Score has declined but also the number of races that have positive scores has fallen from around 57% before divisional play to 44% after.
But since our Race Score gives extra weight to races with multiple teams with good records, this trend can also be attributed to an increasing competitive balance over time. As shown in the graph below for the AL from 1901-2005, the standard deviation in winning percentage has noticeably declined over time (albeit with a number of bumps along the way and a small upturn in the past five years) as the dotted linear trend line indicates. As more teams are bunched closer together, it is statistically less likely that two or more teams will break away from the pack and therefore score very highly in the Race Score metric.
Just why competitive balance has generally increased with time is another story. The most accepted notion, popularized by the late paleontologist and baseball fan Stephen Jay Gould in the context of the disappearance of the .400 hitter , wrests upon two pillars. First, as knowledge about how to play the game has improved and become standardized it has become more difficult for players and hence teams to take advantage of their less skilled competitors. Second, the general level of play has increased due to better athletes produced through a larger population from which the best players are chosen, better diet and training, and better technology, all of which moves the game closer to the limits of human ability providing less space for variation. In the end that leaves great players and great teams, in Gould's words*, less "space for taking advantage of the suboptimality of others".
* The 1996 book Full House: The Spread of Excellence from Plato to Darwin by Stephen Jay Gould contains an extended discussion of Gould's argument. Also see my column "Schrodinger's Bat: The Myth of the Golden Age".