Monday, January 31, 2005

More on explaining the exit polls

A thoughtful post in Left2Right discusses the polling company's analysis of what went wrong in the November 2004 election exit polls, and finds it wanting, based on further analysis of the analysis.

"In the 1970’s and 80’s I worked on election nights for a major network as part of a team of statisticians making “calls” in statewide races (President, Senator, and Governor). Eventually, the team was disbanded because exit polls were so accurate that our expertise was no longer needed."

"But in the past election, the exit polls differed from the recorded vote by an unprecedented amount. Nationwide, exit polls predicted that Kerry had won by 3%, but the final tally showed Bush ahead by 2.5%. Errors in some key states were even larger. As a statistician, I have been concerned that the errors were unexplained..."

"Let me be very clear. I do not assert there was extensive fraud. I would prefer not to think that, and I had hoped the E/M report would reveal a systematic flaw in their methods that accounted for the errors. But it hasn't, and the issue is still open. The E/M report does not account for the biases in a manner that would support explanation (2). The exit polls may well have been flawed, but we have yet to see a plausible account of how or why."

"The data released thus far beg for a more thorough analysis. E/M have not released precinct-level data, which would be necessary to determine whether voting technology is a factor. I hope that they will do so soon. I also hope that the news media report this story so that the public can be widely informed about it. I recognize that if significant problems with the reported vote are found, Republicans will feel that the effort was somehow directed against them. But honest voting is a value that should be supported equally by both Left and Right. We cite discrepancies between exit polls and votes in elections in other countries as evidence of problems. Especially when we have been called to spread liberty and democracy throughout the world, it behooves us to make our own democracy as open and honest as we can."



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