Reply #18: Yup, as I understand it, you are. [View All]

[Febble]

I haven't read the USCV piece in great detail, I'm just talking about the ESI study. My understanding of what they did (and it is not at all clear, so it is possible that I am wrong - I should email them) is that the limits of the "possible" are that ALL the voters selected but not interviewed (i.e. either "missed" or refusers) voted for Bush or ALL for Kerry. ESI would have data on the completion rates for each precinct which include numbers selected, out of which a proportion would be interviewed, a proportion missed, and a proportion would refuse. If ALL refusers and missees were Bush supporters, that would set lower limit (negative WPEs mean Bush voters undersampled) on the plausible WPE and if ALL refusers and missees were Kerry voters, that would set an upper limit. WPEs outside these limits cannot be explained by literal "non-response" bias.

However, WPEs outside these limits CAN be explained, non-fraudulently, if the WPE arose from Kerry voters being selected at a higher rate.

This is hypothetical, but then so are the ESI scenarios: if an interviewer tended to select voters who looked friendly (and of course Kerry voters are all lovely people) then she might get a very high response rate - maybe 10% refusers. ESI's lower limit on her WPE would be whatever it worked out to be if all those refusers were Bushies. But her actual WPE would be much lower than that limit because the problem in that precinct is not that Bushies are refusing to participate when asked, but they are not being asked to participate.

Now that is an exaggerated scenario. But we do know, anecdotally, that people volunteered to participate. And Kiwi has some Ohio anecdotes, specifically that suggest that simply catching voters was a challenge, and we also know that when interviewing rate was low, bias was greater - Bushies may simply have been less easily caught.

This is not to argue that it is what happened (though I believe it probably did) but to argue that WPEs outside ESI's limits of the "possible" are also perfectly capable of an explanation that lies in polling methodology rather than fraud, and is actually supported by some evidence.