Yesterday, Latino Decisions released a new poll showing Obama leading among Latino voters by a staggering 70 to 22 percent margin. While that appears to show Obama poised to exceed his big 67-31 percent victory from 2008, a closer look reveals that Obama’s advantage isn’t quite as enormous as these flashy numbers suggest.
Latino Decisions is an excellent firm, but it’s important to place their numbers in the context of the methodological peculiarities that distinguish them from other pollsters. Latino Decisions believes that the exit polls and most public opinion surveys under-sample Spanish speaking voters, who are more likely to prefer Democrats than their English counterparts. To compensate, Latino Decisions conducts bilingual interviews to reach out to Spanish speakers. They also target Latino voters by contacting common surnames and conducting cell phone interviews, as Latino voters are among the most likely to only use a mobile phone.
These methodological differences have merit, but they change the baseline: We can’t compare Latino Decisions results to other polls or even the exit polls, since even Latino Decisions concedes that their method should produce a more Democratic-friendly sample. Indeed, Latino Decisions actually conducted their own exit poll in 2010 and found significantly higher support for Democratic candidates than the traditional exit poll.
So how should we judge the results of Latino Decisions polls? Fortunately, Latino Decisions offers two highly consistent baselines to assess Obama’s performance. First, Latino Decisions conducted a post-election poll in November 2008, showing that Latinos preferred Obama by a wide 72 to 25 percent margin. Second, the sample for today’s poll voted for Obama by a similar margin, 72 to 23 percent in 2008.
New Latino Decisions polls should be judged on that basis: If Obama holds less than 72 percent of the vote, he’s doing worse than in 2008. That means Obama’s 70 percent share of the Latino vote in yesterday’s poll is impressive, as he's reassembled most of his 2008 coalition—but its hardly extraordinary.
Update, 6:09PM: This piece should not be interpreted to suggest that Latino Decisions only polls individuals with Spanish surnames.