Pew Research: Landline Polling is Skewing Youth Vote, Favoring McCain

from Future Majority

We've been talking about this for at least a year here on Future Majority, but now Pew Research is ready to come out and say it. The number of cell phone-only voters are now numerous enough that their exclusion from traditional polling is skewing the data. A new report from Pew shows that in three straight surveys, lack of cell-only data skewed the survey results 2 - 3% in favor of John McCain.

From the report (emphasis mine):

The Pew Research Center for the People & the Press has conducted three major election surveys with both cell phone and landline samples since the conclusion of the primaries. In each of the surveys, there were only small, and not statistically significant, differences between presidential horserace estimates based on the combined interviews and estimates based on the landline surveys only. Yet a virtually identical pattern is seen across all three surveys: In each case, including cell phone interviews resulted in slightly more support for Obama and slightly less for McCain, a consistent difference of two-to-three points in the margin. [...]

As implied by these results, in each of the three polls, the cell-only respondents were significantly more supportive of Obama (by 10-to-15 percentage points) than respondents in the landline sample. For example, in the September survey Obama led McCain by a 55%-to-36% margin among cell only voters, but the candidates were tied at 45% in the landline sample.

(Continued here.)