NEW YORK -- Two firms that conducted Election Day exit polls for major news organizations reported yesterday that they found a number of problems with the way the polls were carried out last year, resulting in estimates that overstated Senator John F. Kerry's share of the presidential 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 previous group, the Voter News Service, was disbanded.
In November 2000, flawed information from Voter News Service 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. And in the 2002 election, Voter News Service was unable to provide its members and other clients with results from exit poll surveys.
Exit poll material is used to help project 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 on the afternoon of Election Day, several websites posted leaked exit poll material suggesting a Kerry lead.
In an effort to stem any leaks, the news organizations have agreed to withhold the distribution of exit poll information within their organizations in future elections until late in the day, instead of releasing the data in earlier batches.
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.
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.