ung Americans were ditching their landlines in favor of cells, they took comfort in surveys showing that there was little to no difference in how the two groups responded to surveys. Now, a statistically significant difference has been detected, courtesy of the Pew Research Center. As Pollster.com's Mark Blumenthal notes, Pew's researchers concluded that in three surveys from the summer, "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 one would suspect, cell phone users tend to be young -- under 30 -- and they consistently give Barack Obama more than 55% of their vote in these surveys.
Pew's researchers go so far as to conclude that traditional weighting measures are suspect because of the differences between landline voters under 30 and cell phone voters under 30. The differences extend to party identification; the gap between Democrats and Republicans among cell phone-only users was nearly three to one in a recent Pew survey.
So what's next?
Gallup has been sampling a cell-phone only population in conjunction with its landline surveys; see more here.
If Pew's research is correct, then pollsters everywhere will have to adjust their weighting math and rethink how they think about the intersection of technology and public opinion.
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