I think the biggest news out of yesterday’s presidential election, at least for scholars of voting behavior, was the third consecutive meltdown by the national opinion polling service (previously Voter News Service, now Edison/Mitofsky).

What went wrong? Megan McArdle ponders, while the Mystery Pollster explains the process. My gut feeling is that the system in part failed because the networks replaced VNS; Edison/Mitofsky was new at this, and a rookie effort is fraught with perils—as I learned myself yesterday. Coupled, perhaps, with a small cognitive bias on the part of the people being paid by Edison/Mitofsky to conduct the poll themselves (one suspects the typical person looking for day-work isn’t a Republican) and you can easily see why they were quite a bit off, notwithstanding the advertised margin of error.

Contrary to popular wisdom, Andrea Moro says the final exit polls were accurate and has the numbers to prove it. However, that doesn’t quite explain how the networks nearly blew the calls based on the Kerry-leaning numbers they had—and, once you have the final results, it’s easy enough to go back and reweigh the data to match the “true” results; I’d be curious if anyone has hardcopy of the exit poll results, including the weights, dating from before the returns came in.

Me, November 3rd:

My gut feeling is that the [2004 national exit polls] in part failed because the networks replaced VNS; Edison/Mitofsky was new at this, and a rookie effort is fraught with perils—as I learned myself yesterday. Coupled, perhaps, with a small cognitive bias on the part of the people being paid by Edison/Mitofsky to conduct the poll themselves (one suspects the typical person looking for day-work isn’t a Republican) and you can easily see why they were quite a bit off, notwithstanding the advertised margin of error.

Edison/Mitofsky, Wednesday:

[B]ased upon the Within Precinct Error that was observed in the 2004 general election we plan to make some enhancements to the exit poll interviewer recruiting process.

• We will use recruiting methods that reduce the number of students and young adults we use as interviewers.
• In addition to the standardized rehearsal and training dialog, we will add a standardized pre-rehearsal training script for all individual phone training conversations.
• We will evaluate other training techniques such as a video training guide and interviewer tests and use the Internet more effectively as an interviewer training tool. (64)

There’s a lot more there if you really care about exit polling techniques, but the bottom line is that interviewer problems seem to account for much of the pro-Kerry bias in the Edison/Mitofsky poll. (þ: Wizbang)