Presidential Race Maps Writing on the Wall

Polls That Exclude Cell Phones Skew Republican

Posted Nov 23, 2010 at 1:08 AM by Maurice Berger

A just released survey by Pew Research Center suggests that polling organizations that exclude cell phones from their survey tend to produce results that skew sharply Republican: "The number of Americans who rely solely or mostly on a cell phone has been growing for several years, posing an increasing likelihood that public opinion polls conducted only by landline telephone will be biased. A new analysis of Pew Research Center pre-election surveys conducted this year finds that support for Republican candidates was significantly higher in samples based only on landlines than in dual frame samples that combined landline and cell phone interviews. The difference in the margin among likely voters this year is about twice as large as in 2008. Across three Pew Research polls conducted in fall 2010 -- conducted among 5,216 likely voters, including 1,712 interviewed on cell phones -- the GOP held a lead that was on average 5.1 percentage points larger in the landline sample than in the combined landline and cell phone sample. For Pew's more detailed analysis click here.

Polling: The Cell Phone Question

Posted Sep 25, 2008 at 1:21 AM by Maurice Berger

Do pollsters under-represent younger voters by excluding from their samples voters who use cell phones exclusively? Pew Research seems to think so: After including cell phone-only households in three recent polls, the organization notes "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." PollTrack wonders: why then did many public opinion surveys during the Democratic primary season routinely OVER estimate Obama's actual support? And to what extent are pollsters' attempts to weight their samples to correct this deficit solving or adding to the problem? Another question: how do we evaluate Pew's reported discrepancy if the election is not until November and there are no hard results against which to gauge their polling estimates?