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Friday :: Sep 17, 2004
Why You Should Ignore The Gallup Poll This Morning - And Maybe All Of Theirs
This morning we awoke to the startling news that despite a flurry of different polls this week all showing a tied race, the venerable Gallup Poll, as reported widely in the media (USA Today and CNN) today, showed George W. Bush with a huge 55%-42% lead over John Kerry amongst likely voters. The same Gallup Poll showed an 8-point lead for Bush amongst registered voters (52%-44%). Before you get discouraged by these results, you should be more upset that Gallup gets major media outlets to tout these polls and present a false, disappointing account of the actual state of the race. Why?
Because the Gallup Poll, despite its reputation, assumes that this November 40% of those turning out to vote will be Republicans, and only 33% will be Democrat. You read that correctly. I asked Gallup, who have been very courteous to my requests, to send me this morning their sample breakdowns by party identification for both their likely and registered voter samples they use in these national and I suspect their state polls. This is what I got back this morning:
Likely Voter Sample Party IDs ? Poll of September 13-15
Reflected Bush Winning by 55%-42%
Total Sample: 767
GOP: 305 (40%)
Dem: 253 (33%)
Ind: 208 (28%)
Registered Voter Sample Party IDs ? Same Poll
Reflected Bush Winning by 52%-44%
Total Sample: 1022
GOP: 381 (38%)
Dem: 336 (33%)
Ind: 298 (30%)
In both polls, Gallup oversamples greatly for the GOP, and undersamples for the Democrats. Worse yet, Gallup just confirmed for me that this is the same sampling methodology they have been using this whole election season, for all their national and state polls.
According to John Zogby himself:
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.
More at url.