Exit Polls: Mitofsky on News Hour

Exit Polls Legacy blog posts

Warren Mitofsky, one of the principal directors of the National Election Pool (NEP) exit poll, appeared last night on the Lehrer News Hour.  The full transcript is not yet ready, but you can listen to the entire interview via real audio at this link

Mitofsky is arguably the best source for information on this issue, and while the interview does not answer every question, it at least provides his explanation without any filter.  It is worth listening to in full. 

The money quote (my transcription):

Kerry was ahead in a number of the states in margins that looked unreasonable to us, and we suspect that the main reason was that the Kerry voters were more anxious to participate in our exit polls than the Bush voters. That wasn’t the case in every state. We had a few states that overstated the Republican margin, but for the most part it was Democratic overstatement for the reason I just gave you.

What Mitofsky is suggesting is extraordinary: If true, it is the first time in his exit polls and one of the first times I can remember for any political survey, that those who refused to participate in the survey were different enough (more supportive of George Bush) than those who were interviewed to make a material difference in the overall results. 

If it proves true it raises an important question:  Did similar non-response bias also occur on recent telephone surveys?  More on this next week…

UPDATE:  The full transcript of Warren Mitofsky’s interview is now online at this link.

Mark Blumenthal

Mark Blumenthal is the principal at MysteryPollster, LLC. With decades of experience in polling using traditional and innovative online methods, he is uniquely positioned to advise survey researchers, progressive organizations and candidates and the public at-large on how to adapt to polling’s ongoing reinvention. He was previously head of election polling at SurveyMonkey, senior polling editor for The Huffington Post, co-founder of Pollster.com and a long-time campaign consultant who conducted and analyzed political polls and focus groups for Democratic party candidates.