One reason we constantly hear about the Gender Gap in voting even though all the evidence from Presidential election years suggests the Marriage Gap is more important is because the exit polls during the midterm elections usually forget to ask respondents if they are married.

For example, here’s CNN’s 2010 exit poll data for House of Representatives races. There’s no mention of marriage whatsoever. CNN did do a crosstab of race and sex, which shows that in the 2010 election the Gender Gap was quite small: among white men, GOP House candidates won 62-34 and among white women, the GOP won 58-39.