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Thursday, January 20, 2005

Exit Poll Analysis

There have been many claims of voting fraud and that Bush stole the election. The primary indicator of potential fraud was A study by Steven Freeman at the University of Pennsylvania looking at differences in exit polling results and counted votes. It states that:
"As much as we can say in social science that something is impossible, it is impossible that the discrepancies between predicted and actual vote counts in the three critical battleground states [Ohio, Florida, and Pennsylvania] of the 2004 election could have been due to chance or random error."
Note that because the study only identified a discrepancy, Freeman concluded with the following:
"Systematic fraud or mistabulation is a premature conclusion ..."
With the release of a study analyzing exit polling for the last election, I'm now pretty convinced that fraudulent activities regarding voting and vote counting, if any, played an insignificant role and that the election was not stolen. The study is an internal report performed by the organizations that did the exit polling for the news services. The report identifies "some factors that appear to have contributed" to the discrepancy between exit polling and actual vote counts:
  • Distance restrictions imposed upon our interviewers by election officials at the state and local level
  • Weather conditions which lowered completion rates at certain polling locations
  • Multiple precincts voting at the same location as the precinct in our sample
  • Polling locations with a large number of total voters where a smaller portion of voters was selected to be asked to fill out questionnaires
  • Interviewer characteristics such as age, which were more often related to precinct error this year than in past elections
The last point seems the most significant, and fortunately, the most easily corrected for future elections. Elaborating on the last point, the report states:
Older interviewers had lower WPE [Within Precinct Errors] than the youngest interviewers. They also had better completion rates. This does not necessarily mean that the younger interviewers did poorly at their task. It does indicate that in this election voters were less likely to complete questionnaires from younger interviewers.
And the younger interviewers seemed to have more trouble with the voters as well. Interviewers who were 18-24 years old found that only 27% of the voters were "very cooperative" while interviewers who were 55 or older found 69% of the voters "very cooperative".

The early exit poll numbers that were leaked to Drudge and other alternative media outlets during the afternoon of November 2nd that showed Kerry ahead by a wide margin were due to a "programming error":
Early in the afternoon on November 2nd, preliminary weightings for the national exit poll overstated the proportion of women in the electorate. This problem was caused by a programming error involving the gender composition that was being used for the absentee/early voter portion of the national exit poll. This error was discovered after the first two sets of weighting; subsequent weightings were corrected. This adjustment was made before NEP members and subscribers used exit poll results on-air or in print.
Another line of evidence for fraud is also addressed:
Some have suggested that the exit poll data could be used as evidence of voter fraud in the 2004 Election by showing error rates were higher in precincts with touch screen and optical scan voting equipment. Our evaluation does not support this hypothesis. In our exit poll sample overall, precincts with touch screens and optical scan voting have essentially the same error rates as those using punch card systems. In the larger urban areas these systems had lower WPEs than punch card precincts.
Of course, that's not to say that we shouldn't make our voting systems better.

The report lists some changes that will hopefully improve future exit polls but gives the following cautionary note:
Even with these improvements, differences in response rates between Democratic and Republican voters may still occur in future elections.
This is why we have people actually vote instead of just doing exit polling. If exit polling were perfect, we could save a lot of money by not bothering with the polls, except in exceptionally close races. I feel the discrepancies between predicted and actual vote counts, cited by the Freeman study, are now adequately explained.

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