Princeton Election Consortium

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Wrong Assumptions

November 3rd, 2004, 11:30am by Sam Wang


To summarize points so far this morning: So far, the electoral outcome matches pre-election polling data very closely, with the possible exception of Florida. Therefore the electoral count looks a lot like the decided-voters median listed above. However, my final predictions were wrong. It appears that my add-on assumption about undecideds (the rule that they break against the incumbent) was wrong; this may have been because of the war, as suggested by the Mystery Pollster. My turnout assumption was also wrong. Exit polls do match my projection, which is surprising to me. This could be because those data are somehow non-representative, for instance because of gender bias.

Specific comparisons: victory margins were predicted well by polls. Out of 23 battlegrounds, the direction of the outcome was predicted in 22. The exception was Wisconsin, where the polling margin was 0.4% for Bush and the actual margin was about 0.4% for Kerry. Quantitatively, 12 victory margins were within one standard error and 17 were within the 95% confidence interval. Not perfect, but not bad.

Tags: 2004 Election

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