Public opinion surveys are central to the Iranian opposition's argument that the elections there were rigged for incumbent President Mahmoud Ahmadinejad: they cite unspecified polls showing the main challenger, Mir Hossein Mousavi with a "strong lead in the final days of the campaign," according to the New York Times.
Now, a competing poll conducted by two American groups is being used as part of the pushback. In an op-ed in today's Washington Post, Ken Ballen and Patrick Doherty write-up the results of their telephone poll carried out in mid-May, showing Ahmadinejad ahead "by a more than 2 to 1 margin - greater than his actual apparent margin of victory in Friday's election."
The validity of the unreleased Iranian surveys cannot be assessed in detail, but a closer look at the one sponsored by Terror Free Tomorrow and the New America Foundation reveals ample reason to be skeptical of the conclusions drawn from it.
Methodologically, this survey passes muster as it's relatively straightforward to pull a good sample of the Iranian population, using the country's publicly available population counts and listed telephone exchanges. But the poll was conducted from May 11 to 20, well before the spike in support for Mousavi his supporters claim.
(See here for a summary of available Iran polls that finds some evidence for Mousavi momentum late in the campaign.)
More to the point, however, the poll that appears in today's op-ed shows a 2 to 1 lead in the thinnest sense: 34 percent of those polled said they'd vote for Ahmadinejad, 14 percent for Mousavi. That leaves 52 percent unaccounted for. In all, 27 percent expressed no opinion in the election, and another 15 percent refused to answer the question at all.
Six Eight percent said they'd vote for none of the listed candidates; the rest for minor candidates.
One should be enormously wary of the current value of a poll taken so far before such a heated contest, particularly one where more than half of voters did not express an opinion.