For two months now the Official Line has been that the ONLY possible reason the exit polls leaned more to Kerry than the election result was Official Vote Stealing.
Now, to be sure there were problems, especially in the allocation of resources (more machines in GOP precincts, etc.) And maybe as someone who's seen the election process from every conceivable angle - journalist, party staffer, candidate and election office worker - I just have trouble believing the black-box theories.
But this article (in annoying pdf) looks at some reasonable, survey-statistic reasons for the mismatch. All this will of course be dismissed by the conspiracy minded and buried by the inauguration:
The problem is that Kerry voters were more likely to fill out exit poll questionnaires than Bush voters. There's no way to really prove this, but they offer several suggestive statistics:
The error rate was smaller in precincts where the interviewers attempted to survey every voter. Error rates went up in larger precincts where interviewers surveyed every third or every tenth voter. Error rates were higher in swing precincts (those that had approximately equal numbers of Democrats and Republicans). Older interviewers had smaller error rates than younger interviewers. Error rates went up significantly if interviewers were required to stand 100 feet away from the polling place.
The report's conclusion is that when they had greater discretion (i.e., in swing precincts and in larger precincts where they couldn't interview everyone), younger interviewers unconsciously tended to select younger voters, who were more likely to have voted for Kerry.
(Haven't read the whole annoying pdf but I'd like to see the data correlated by interviwer/interviewee gender. It's a reality that the election day labor pool of poll workers, party volunteers, and exit pollers is stretched thin and is not supervised on an every-minute basis. Could the whole controvery be explained by interviewers unconsciously or semi-consciously choosing to talk to the Cute One or the Hot One instead of the Little Old Lady?)
Likewise, younger voters were more likely than older voters to agree to fill out a survey from a young interviewer.
No other source of error appears to have been present, so the error must have come — somehow — from an oversampling of Kerry voters in individual precincts.
All this seems more plausible than "h@ck3r$ h@ck3d the votining equipment."
I'll go back to my old standby: there's no way for pollsters to control for the "none of your damn business" response. Which demographics are more likely to refuse to respond? What underlying opinions and attitudes are reflected by refusal to respond? We don't know!