Competitiveness in Major League Baseball

Yesterday marked the final regular-season games of the 2014 season of major league baseball (MLB), In observance of that event, I’m shifting from politics to competitiveness in MLB. What follows is merely trivia and speculation. If you like baseball, you might enjoy it. If you don’t like baseball, I hope that you don’t think there’s a better team sport. There isn’t one.

Here’s how I compute competitiveness for each league and each season:

INDEX OF COMPETITIVENESS = AVEDEV/AVERAGE; where

AVEDEV = the average of the absolute value of deviations from the average number of games won by a league’s teams in a given season, and

AVERAGE =  the average number of games won by a league’s teams in a given season.

For example, if the average number of wins is 81, and the average of the absolute value of deviations from 81 is 8, the index of competitiveness is 0.1 (rounded to the nearest 0.1). If the average number of wins is 81 and the average of the absolute value of deviations from 81 is 16, the index of competitiveness is 0.2.  The lower the number, the more competitive the league.

With some smoothing, here’s how the numbers look over the long haul:

Index of competitiveness
Based on numbers of wins by season and by team, for the National League and American League, as compiled at Baseball-Reference.com.

I drew a separate line for the American League without the Yankees, to show the effect of the Yankees’ dominance from the early 1920s to the early 1960s, and the 10 years or so beginning around 1995.

The National League grew steadily more competitive from 1940 to 1987, and has slipped only a bit since then. The American League’s climb began in 1951, and peaked in 1989; the AL has since slipped a bit more than the NL, but seems to be rebounding. In any event, there’s no doubt that both leagues are — and in recent decades have been — more competitive than they were in the early to middle decades of the 20th century. Why?

My hypothesis: integration compounded by expansion, with an admixture of free agency and limits on the size of rosters.

Let’s start with integration. The rising competitiveness of the NL after 1940 might have been a temporary thing, but it continued when NL teams (led by the Brooklyn Dodgers) began to integrate, by adding Jackie Robinson in 1947. The Cleveland Indians of the AL followed suit, by adding Larry Doby later in the same season. By the late 1950s, all major league teams (then 16) had integrated, though the NL seems to have integrated faster. The more rapid integration of the NL could explain its earlier ascent to competitiveness. Integration was followed in short order by expansion: The AL began to expand in 1961 and the NL began to expand in 1962.

How did expansion and integration combine to make the leagues more competitive? Several years ago, I opined:

[G]iven the additional competition for talent [following] expansion, teams [became] more willing to recruit players from among the black and Hispanic populations of the U.S. and Latin America. That is to say, teams [came] to draw more heavily on sources of talent that they had (to a large extent) neglected before expansion.

Further, free agency, which began in the mid-1970s,

made baseball more competitive by enabling less successful teams to attract high-quality players by offering them more money than other, more successful, teams. Money can, in some (many?) cases, compensate a player for the loss of psychic satisfaction of playing on a team that, on its record, is likely to be successful.

Finally,

[t]he competitive ramifications of expansion and free agency [are] reinforced by the limited size of team rosters (e.g., each team may carry only 25 players from May through August). No matter how much money an owner has, the limit on the size of his team’s roster constrains his ability to sign all (even a small fraction) of the best players.

It’s not an elegant hypothesis, but it’s my own (as far as I know). I offer it for discussion.

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Other related posts:
The End of a Dynasty
What Makes a Winning Team
More Lessons from Baseball
Not Over the Hill