Wednesday, February 3, 2010

Republican Groupthink or Statistical Ho-Hum?

The sentiment among Republicans by demographic (via FiveThirtyEight).

FiveThirtyEight uses a Daily Kos poll to emphasize this conclusion:
On just about every question, the results showed essentially no difference based on age, gender, race, or geography -- once we've established that you're a Republican, these differences seem to be rendered moot.
Many people seem outraged by this finding, but I'm not surprised by it. For these same questions, once we've established that you're a Democrat, we would expect similar results (though of course very few will respond that they think Obama is a racist or should be impeached).

If an econometrician or other serious scientist proposed doing a regression to show the causes of support for sex education in schools (another question in the poll), including party affiliation as a factor would make sense, but including gender would not. There is no ex ante expectation that gender will influence one's beliefs on the subject. You can't construe your hypotheses after running your experiments. If you look at 20 treatments, odds are, at least one will show a statistical significance by sheer coincidence (see the file drawer effect).

The author argues that the Republicans:
don't have to worry about the constellation of constituencies that Democrats have: labor voters, Baby-boomer liberals, blacks, Hispanics, college-educated technocrats, libertarianish younger voters, etc. Their base is the same pretty much everywhere, and actuating a strategy that appeals to that base is not challenging.
Note that many of the purported Democratic subcategories would not be accounted for anyway when the poll only reports result by gender, race, age, and region. Also, if you subscribe to median voter theory, the extremes of the Democratic Party—and the various sources thereof—shouldn't even be an issue. In a two-party election, a Democratic candidate's platform should be aimed at the voters in the middle, as the liberal extremists will vote for him anyway.