http://www.washingtonpost.com/wp-dyn/articles/A41186-2004Jan23.html?nav=hptoc_pWhy do so many pollsters go squinty-eyed when Zogby's name is mentioned? Here are some of their biggest complaints about the ubiquitous pollster from Utica:
Zogby draws his samples only from computer files of people with listed telephone numbers, thereby missing 30 percent of the population with unlisted telephone number.
The biggest advantage to what Zogby does is that most of those telephone numbers are good. The disadvantage is that you miss everyone with an unlisted number, and people with unlisted numbers tend to be different than those who are in the telephone book. Most other public pollsters rely on Random Digit Dialing, a technique that captures both listed and unlisted numbers. (Zogby says he plans to release a study later this year that shows no demographic or ideological differences between people with listed numbers and those who are unlisted.)
Zogby also calls people during the day as well as in the evening. About 30 percent of his interviews are collected before 5:30 p.m. Daytime interviews are great if you want to talk to lots of retirees and housewives. But his critics charge that they're not so good if you want to interview working men and women. Zogby counters that daytime interviewing actually produces a more representative sample because he can talk to people who work at night.
Zogby also adjusts his sample based on historic trends and his judgment of "what is happening on the ground" in a particular race, and it is this imposition of his own judgment that disturbs many pollsters.
He will, for example, reduce the proportion of 18- to 24-year-olds in his sample of self-described likely voters if he suspects on the basis of past voting history and the "lay of the land" that a sample contains too many younger people. He also, on occasion, adjusts the religious composition of his sample if he suspects he has over or under-represented one faith.
Most pollsters cringe at such extra-curricular adjustments. "I know I do some things different that others," he said. "I know the so-called 'Poll-ice' would deny it, but there's art as well as science involved in this."