NEW YORK - Two firms that conducted Election Day exit polls for major news organizations reported Wednesday that they found a number of problems with the way the polls were carried out last year, resulting in estimates that overstated John Kerry's share of the vote.
Edison Media Research and Mitofsky International found that the Democratic challenger's supporters were more likely than President Bush's supporters to participate in exit poll interviews. They also found that more errors occurred in exit polls conducted by younger interviewers, and about half of the interviewers were 34 or under.
The polling firms laid out their findings to the consortium of news organizations, known as the National Election Pool.
The news organizations - ABC, CBS, NBC, CNN, Fox News and the Associated Press - formed the consortium to get exit polling data for the 2004 election after a group known as the Voter News Service was disbanded.
In November 2000, flawed information from VNS twice led television networks to incorrectly declare a winner in the presidential race in Florida, the state that proved to be key to the outcome.
Exit poll material is used to help make projections of winners and to supplement the vote count with an analysis of why people voted as they did. The data are not meant to be made public before polls close in a state, but several Web sites posted leaked poll material on the afternoon of Election Day 2004 suggesting a Kerry lead.
Edison and Mitofsky said problems contributed to exit poll data that overstated the vote for Kerry nationally and in 26 states, while data for four states overstated the vote for Bush.
They noted that in a number of precincts, interviewers were kept 50 feet or more away from polling places, potentially skewing results toward people motivated to go out of their way to participate in exit polls. They also found suggestions that interviewers may not have carefully followed rules for selecting voters at random, which may have skewed results.
The polling firms said they believed the exit poll errors were not the result of the selection of precincts where the interviews took place or the analysis of the data. They also said they found no evidence to suggest fraud by rigging of polling equipment.
Despite the problems, the firms noted that they still made correct calls for all races on election night.