Telephone polling: Currently a flawed measure of voting preference

Obama’s Lead Looks Stronger in Polls That Include Cellphones

By NATE SILVER, NYT

As I observed on Tuesday, and as The New Republic's Nate Cohn also found, Barack Obama seems to have received a much clearer bounce in some types of polls than others.

Although there are exceptions on either side, like the Gallup national tracking poll, for the most part Mr. Obama seems to be getting stronger results in polls that use live interviewers and that include cellphones in their samples - enough to suggest that he has a clear advantage in the race.

In the polls that use an automated dialing method ("robopolls") or which exclude cellphones, Mr. Obama's bounce has been much harder to discern, and the race looks considerably closer.

The difference seems especially pronounced at the state level. Mr. Obama got very strong results in a series of NBC News/Marist College polls last week in Ohio, Florida and Virginia, which included cellphones and used live interviewers. Likewise, Tuesday morning's series of New York Times / CBS News / Quinnipiac polls had reasonably good news for Mr. Obama in Virginia and Wisconsin.

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