Thursday, September 09, 2004

I'm Always Suspicious of Political Polls.

Do you ever suspect that political polls are just that, suspect? Three polls have come out since the Republican convention and two of them are reflecting a post convention bump for President Bush. The Time and Newsweek polls show a big gain for Bush in contrast to the Zogby poll. Well, John Zogby addressed this difference recently and I find his explaination intriguing. From his letter he writes,
Two new polls came out immediately after mine (as of this writing) by the nation's leading weekly news magazines. Both Time's 52% to 41% lead among likely voters and Newsweek's 54% to 43% lead among registered voters give the President a healthy 11 point lead. I have not yet been able to get the details of Time's methodology but I have checked out Newsweek's poll. Their sample of registered voters includes 38% Republican, 31% Democrat and 31% Independent voters. If we look at the three last Presidential elections, the spread was 34% Democrats, 34% Republicans and 33% Independents (in 1992 with Ross Perot in the race); 39% Democrats, 34% Republicans, and 27% Independents in 1996; and 39% Democrats, 35% Republicans and 26% Independents in 2000. While party identification can indeed change within the electorate, there is no evidence anywhere to suggest that Democrats will only represent 31% of the total vote this year. In fact, other competitors have gone in the opposite direction. The Los Angeles Times released a poll in June of this year with 38% Democrats and only 25% Republicans. And Gallup's party identification figures have been all over the place.

This is no small consideration. Given the fact that each candidate receives anywhere between eight in ten and nine in ten support from voters in his own party, any change in party identification trades point for point in the candidate's total support. My polls use a party weight of 39% Democrat, 35% Republican and 26% Independent. Thus in examining the Newsweek poll, add three points for Mr. Bush because of the percentage of Republicans in their poll, then add another 8% for Mr. Bush for the reduction in Democrats. It is not hard to see how we move from my two-point lead to their eleven-point lead for the President.
Is it so hard to believe that Bush is doing better in the Newsweek poll when their sample has more Republicans than Democrats? No surprise to me. And Zogby points out in recent elections that Democrats vote at a higher percent than Republicans. The Newsweek poll is skewed to reflect a Republican viewpoint.

One wonders if Newsweek is doing this on purpose. By having a poll result that makes it look like Bush is doing better than he might really be doing, that poll encourages Republicans. With results like the Newsweek poll and if they continue to skew their party demographic in future polls it would possibly cause Democratic voters to not show up and vote. There is also the "bandwagon effect" where voters like to cast their vote for a winner, a sort of personal pride in siding with the winning candidate.

I'm suspicious of the Newsweek poll. Is it possible that Newsweek is pulling for Bush and producing poll results that might influence the race? At the least, their poll is suspect as accurate by skewing the political party demographic.

Full letter of John Zogby...


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