Thursday, October 28, 2004
Disregard Zogby's Polling
I had been urging readers to keep careful attention to the Zogby polls, considering his accuracy in 1996 and 2000. Now, a report on The Horserace blog does a deep analysis of his and other polls. This is a must read. His convincing conclusion: Zogby's polls are biased. See his specific comment on Zogby below, but you must read the entire entry in Horserace
"[D. J.] Drummond seems to think that Zogby simply fell ass-backward into his present notoriety. Zogby predicted 1996 accurately and came close in 2000. However, his track record is generally lousy. Zogby has a devastating methodological problem -- his polls are not conducted randomly. He uses regional quotas. He is the only one of all these polls (that make any methodology known) that employs this technique. Furthermore, Zogby does not conform his data to industry standards. Rather, he uses -- among other sources -- his previous data. Neither of the standard-setters in the polling industry accept this practice. Zogby also weights his polls to strictly conform with the 2000 partisan turnout results -- a result that BC04 has spent tens of millions of dollars to change. Zogby, a supposedly independent pollster, also called the race for Kerry...IN THE SPRING! Zogby is also one of the chief practitioners of the internet poll, which is really quite unacceptable. Because I have (unfortunately) used Zogby here at this site, I will quote the very estimable Drummand at length (consider it part of my pennance): "All in all, Zogby’s habit of confusing his personal opinion with data-driven conclusions, his admitted practice of manipulating the respondent pool and his demographic weights, by standards not accepted anywhere else, along with mixing Internet polls with telephone interview results, forces me to reject his polls as unacceptable; they simply cannot be verified, and I strongly warn the reader that there is no established benchmark for the Zogby reports, even using previous Zogby polls, because he has changed his practices from his own history."
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