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July 07, 2006

Pew Interview: Mitofsky on the Mexican Exit Polls

This week's belated focus on the U.S. exit poll controversy was well timed, as exit polls once again made news, this time in the Mexican elections.  An exit poll conducted by Warren Mitofsky for Mexican television network Televisa showed the election too close to call, and the vote count reported Felipe Calderón ahead of his main opponent, Andrés Manuel López Obrador, by razor thin margin (35.88% to 35.31%).   So how could the exit polls in Mexico have been right in Mexico, but off in the 2004 U.S. elections?  The Pew Research Center brings us the explanation from Warrent Mitofsky in an interview conducted by pollster Andrew Kohut.

The interview is definitely worth reading in full, but here is the most pertinent excerpt:

What is the biggest difference between conducting an exit poll in Mexico compared to doing one in the United States? And why do you think this poll was so much more accurate than the exit polls for the 2004 presidential election?

There are a few important differences: One is that the response rate is a lot better in Mexico. Also, we train the interviewers in person rather than by telephone. Third is that when we do the research we cannot get maps, which causes a problem. But we get good records, good cooperation.

And we did one thing that hopefully I learned from the 2004 election: We insisted in the personal training of the interviewers that they absolutely stick to the sampling rate. And if there is a refusal they continue the count to the next sample person; they don't substitute anyone in between.

So if I understand correctly, if I, the interviewer, am to talk to every fifth person coming out the door and that person refuses, I don't go to the next person. Instead I go to the next fifth person who comes out?

Right, there was no bias in this exit poll at all. In a typical Mexican exit poll we overstate the PRI, which was the government party that ran the country for the past 70 years, but which finished third this time around. We usually overstate PRI and understate the other two parties. This time the other two were understated by a fraction of a percent and offset each other so there was essentially no bias in the exit poll. I did the same thing in another exit poll elsewhere and there was no bias there either.

Despite Mitofsky's report of "absolutely no leaks in the results," Greg Palast has argued, oddly, that exit poll showed "the voters voted for the progressive candidate."    See this blog post for a contrary opinion.  Mexico's PRI party also seems to disagree

Related Entries - Exit Polls

Posted by Mark Blumenthal on July 7, 2006 at 08:52 AM in Exit Polls | Permalink


What's starting to really cause people to raise eyebrows is
a) a series of close elections
b) that are run by conservaties/the right wing
c) that the conservative candidate ekes out a win in.

One starts to wonder if it's even possible for the conservatives in Mexico (or Ohio, Florida, Georgia [think Black Sea]) to run a tight, close, fair election where their own candidate loses.

I have no evidence or feel for what happened in Mexico. But pretty soon this kind of occurrence is going to lead to an open rebellion. People are starting to get extremely pissed off. Another Ken Blackwell miracle in Ohio would be a possible trigger.

Posted by: RickD | Jul 7, 2006 1:41:13 PM

If people get pissed off, they should work harder to make sure they win the next election. There are a few reasons conservatives might win close elections, including money, better organized GOTV and advertising. An illegitimate reason for winning like voter suppression (not fraud) and long lines in poorer districts is a major concern which can only be dealt with by better scrutiny and more involvement, including winning local elections to better control the mechanics.

Simply complaining about it does nothing.

Posted by: DemFromCT | Jul 7, 2006 2:25:42 PM

Warrent Mitofsky's confidence in Mexico's IFE (Federal Election Institute) seems misplaced to me. The IFE's initial results are based on precint tallies, but there are, as Narconews (http://www.narconews.com/Issue42/article1967.html) has reported, widespread variations between these tallies and the actual numbers that went into the IFE's intitial tabulation of the results. Aggregate these variations and you have a Calderon victory. Lopez Obrador's demand for a recount threatens to undo this, which is why the PAN and its media allies are resisting it so intensely.

Posted by: Rick Coughlin | Jul 26, 2006 10:17:49 PM

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