Are black NBA fans less loyal to their home teams?

Black NBA fans seem to be less loyal to their hometown teams than non-black NBA fans, the New York Times has found.

Here's the article, from Nate Cohn of The Upshot. It found data showing that, in ZIP codes where at least 40 percent of residents are black, the home team got a significantly smaller proportion of Facebook "likes" than in other ZIP codes. In Milwaukee, for instance, the map highlighting black areas is almost identical to the map highlighting areas where more fans prefer teams other than the Bucks. Here are those stolen maps:

It's a very interesting finding. But, I'm not convinced it's a race thing.

In general, what can you say about sports fans whose favorite team isn't their own city's?  It seems like they're more serious fans. Here in Ottawa, we have a lot of fans who are ... not bandwagon jumpers, but just people who support the team, by default, because it's the Ottawa team. A lot of them don't know that much about the players, or hockey in general.

But fans who support unlikely teams, like the Sharks or the Predators, probably have more than a passing interest in the NHL. Maybe they like the style of play, or one of their favorite players is there, or even, they want to root for a more successful team.  

Might that explain what's happening in Milwaukee? As it turns out, blacks are indeed more likely to be serious NBA fans. The second sentence of the article says,

"About 45 percent of people who watched N.B.A. games during the 2012-2013 regular season were black, even though African-Americans make up 13 percent of the country's population."

So, what I suspect is that at least part of the explanation is that black areas are being confounded with "high fan interest" areas.  I have no evidence of that, and I might be wrong.  (But, the article has no evidence against it, either.)

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It's not just Milwaukee: Cohn discovered the same effect in Cleveland, Memphis, Atlanta, Detroit and Chicago. But, interestingly, there was no effect in Houston, Philadelphia, Dallas, and Washington.  

What would the difference be? Maybe the success of the teams?  The "disloyal" cities' teams averaged 35.5 wins this past season, and four of the six had losing records. The "loyal" fans' teams averaged 41.5, and only one of the four was below .500 (Philadelphia, at 19-63).

That's something, but it doesn't seem that strong.  

Are there be some cities where it's culturally acceptable to root for a different team, and other cities where it's not? Is this one of those random "tipping point" things?

Are basketball fans -- or even black basketball fans -- more fervent in Cleveland than they are in Houston? Probably not ... the Neilsen TV demographics report (.pdf), from which the "45 percent of viewers were black" statistic was taken, shows that Dallas and Chicago were almost identical in the percentage of the population that watches or listens to games.

Is the distinction just one of statistical significance, where Houston *does* have a strong effect, just not strong enough to be 2 SD from zero? Maybe it's that some cities are less segregated by ZIP code than others, so the effect is still there but doesn't show up in maps?

Could it be that there are more natural, opposing loyalties some places than others? Here in Ottawa, we have a ton of Leafs fans and Canadiens fans, because the Ottawa team is relatively new, and people hang on to the teams they loved in their childhoods. Did Milwaukee fans grow up rooting for Michael Jordan and the Bulls, which is why they formed weaker attractions to their Bucks? That sounds plausible, but then, it's hard to explain why the same thing holds for the Chicago area.

Any other ideas? Anybody see anything else that might be a relevant distinction between the two groups of cities?