Don undecided voters break sharply for the challenger?
Undecided voters probably sometimes break sharply for the challenger. But I can find no evidence that this rule is useful in “allocating” reported undecided voters in presidential elections. In fact, overall, reported undecideds seem to break about evenly. In support of the claim that undecideds break for the challenger, TruthIsAll has cited an essay by Chris Bowers at MyDD. Bowers canvassed 28 presidential polls going back to 1976, and concluded that “undecideds break overwhelmingly — better than 6 to 1 — in favor of the challenger in a Presidential race.” But a close reading reveals that Bowers did not examine declared “undecided” voters at all! Bowers basically found that on average, incumbents did about 0.3 points better than the final polls indicated, while challengers did about two points better indeed a ratio of more than 6 to 1. This result mostly had nothing to do with undecided voters. Nine of the 28 surveys were from 1996, a year in which the pre-election polls overstated
