Telephone poll

By Mustang Bobby

Chances are if you get polled by a political survey, they’re going to do it on your land-line phone. But what about those people who have given up their land-lines and use cellphones only? Nate Silver at FiveThirtyEight ran the numbers, and it has an interesting outcome:

We keep track of which polling firms include cellphones in their samples and which do not. So on Monday night, I decided to run two alternate versions of the FiveThirtyEight forecast. (Note that all results are based on polls that were in our database as of Monday night, and so will not include Tuesday morning's New York Times polls or others published on Tuesday.)

In one of the forecasts, I ran the numbers based solely on polls that do include cellphones in their samples. The vast majority of these polls also use live interviewers, since federal law prohibits automated calls to cellphones under most circumstances. (Note, however, that one or two mostly automated polling firms, like SurveyUSA, use a separate sample based on live interviewers to reach cellphone-only voters; these were included in the model run.)

In this universe, Mr. Obama seems poised for victory. The model forecasts him for a 4.1 percentage points win in the national popular vote. That compares with 2.9 percentage points in the regular FiveThirtyEight forecast, which includes polls both with and without cellphones.

Mr. Obama's advantage is also clearer in the swing states. The cellphone-inclusive polls give him an 80 percent chance to win Virginia, a 79 percent chance in Ohio, and a 68 percent chance to win Florida, all considerably higher than in the official FiveThirtyEight forecast.

Overall, this version of the model gives Mr. Obama an 83 percent chance of winning the Electoral College, a full 10 percentage points higher than the 73 percent chance that the official FiveThirtyEight forecast gave him as of Monday night. So the methodological differences are showing up in a big way this year.

I'm curious as to why this would be the case; cellphone usage is universal regardless of political affiliation. Maybe it has something to do with the fact that robo-polling is prohibited on cellphones, whereas anyone with a landline knows that robo-polling ("If you support Barack Obama, press 1") is rampant and probably unreliable since they have no idea who is responding to the poll.

If this model holds true, we're looking at a much bigger win for President Obama.

(Cross-posted at Bark Bark Woof Woof.)