Competitive (im)Balance: Division by Division Performance

We live in an era of baseball history that is much lauded for its competitive balance. Loads of teams are in contention for a playoff berth until very late in the season. Each season, I like to look at the relative performance of baseball's leagues and divisions as a whole to get a better sense of team quality. Essentially, I am trying to correct to some degree for the unbalanced schedule.

While the 2016 season isn't quite over, we're rapidly approaching the end of the season and most remaining games are within division, so they won't move the needle on these metrics.

Let's take a look at the record of each division against non-divisional opponents and overall run differential (which automatically reflects only out-of-division differences because within-division run differential is by definition 0).

National League East: 199-214 (.481), -137

National League Central: 210-202 (.510), +97

National League West 193-219 (.468), -79

National League Interleague: 126-159 (.442), -119

American League East: 223-189 (.541), +238

American League Central: 204-209 (.494), -79

American League West: 209-204 (.506), -40

American League Interleague: 159-126 (.558), +119


There are a few takeaways from this, I think. Firstly, the American League is plainly better than the National League. Some have argued that NL teams are at a disadvantage in interleague games because of the implementation of the DH rule. There might be some truth to this, but I doubt it explains a difference of this size. I suspect we could get some vague idea of the likely impact of the DH rule if we take enough interleague data from AL parks and look at the degree to which AL teams overperform their expected home-field advantage (if any). We'd probably need several years worth of data to cut through the noise.

The AL East and the NL Central are again clearly the best divisions in their leagues. In fact, they are the only divisions in baseball with a positive run differential. This is particularly damning for the AL West and Central, who still have a negative run differential despite the fact that they get to pad that against weaker NL competition. The AL East seems to be by far the best division in baseball. Similarly, contending teams in the NL East and West are likely substantially worse than their records suggest given how weak their divisions are.

Based on these results (and similar results for the past several years), I'd argue that competitive balance in baseball is less a product of relative balance between teams and more a product of the way that the unbalanced schedule allows otherwise mediocre teams in soft divisions to compete. It seems like baseball has one very strong division (AL East), one strong division (NL Central), three weak divisions (AL West, AL central, and NL West with the AL divisions having a substantial edge over the NL), and one very weak division (NL East).

Is this actual competitive balance? Do you think these patterns will become more extreme over time with teams in weak divisions deciding to coast while teams in strong divisions are forced into a perpetual arms race to keep up with divisional rivals?
 

crystalline

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SoSH Member
Oct 12, 2009
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JP
Is this actual competitive balance? Do you think these patterns will become more extreme over time with teams in weak divisions deciding to coast while teams in strong divisions are forced into a perpetual arms race to keep up with divisional rivals?
Cool.

I'm not sure there are factors that cause instability in competitive balance (I.e. arms races making good divisions better or low revenues making bad divisions worse). Rather than such feedback factors, I suspect the differences are structural: the Yankees and Red Sox and Rays and now Os have good management. So do the Cubs and Cards.

Skilled management first and high revenues second (owning your TV station, high gate revenues) are what lead to the imbalance, I think.

P.s. If that's true, then it should show up in teams' five year interleague records.