Let's see if I can drag this thread back to an adult conversation about the issue at hand. I'm sure the kids will pop back in with their little tantrums, but what the hell, it's always worth a shot.
The Dukakis lead is an interesting example of how things can change, but I don't get that vibe this time. The polls really haven't changed much, even when one of the candidates "has a bad week". Everyone keeps pointing toward the debates, so convinced that their guy will run away with it after that. Maybe.
Right now most polls have Obama up somewhere around 47-45, leaving 8% out of it. I'd like to know how much of that 8% is undecided and how much of it will be voting for an alternate party.
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The undecideds won't vote for the incumbent
You're saying that's how it's been historically, that undecideds usually break to the challenger?
I also wonder if 8% is a high, low or normal figure for 4 months out.
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How will undecideds vote on election day? Traditionally, there have been two schools of thought about how undecideds in trial heat match-ups will divide up at the ballot box. One is that they will break equally; the other, that they will split in proportion to poll respondents who stated a candidate preference.
But our analysis of 155 polls reveals that, in races that include an incumbent, the traditional answers are wrong. Over 80% of the time, most or all of the undecideds voted for the challenger.
The 155 polls we collected and analyzed were the final polls conducted in each particular race; most were completed within two weeks of election day. They cover both general and primary elections, and Democratic and Republican incumbents. They are predominantly from statewide races, with a few U.S. House, mayoral and countywide contests thrown in. Most are from the 1986 and 1988 elections, although a few stretch back to the 1970s.
The polls we studied included our own surveys, polls provided to us directly by CBS, Gallup, Gordon S. Black Corp., Market Opinion Research, Tarrance Associates, and Mason-Dixon Opinion Research, as well as polls that appeared in The Polling Report.
In 127 cases out of 155, most or all of the undecideds went for the challenger:
DISPOSITION OF UNDECIDED VOTERS
Most to challenger....127
Split equally.................9
Most to incumbent.....19
The fact that challengers received a majority of the undecided vote in 82% of the cases studied proves that undecideds do not split proportionally. If there were a tendency for them to split proportionally we would see most undecided voters moving to incumbents, since incumbents win most elections. Similarly, even accounting for sample error, it's clear from the chart above that undecideds do not split equally.
For poll users and reporters this phenomenon, which we call the Incumbent Rule, means: Incumbent races should not be characterized in terms of point spread. If a poll shows one candidate leading 50% to 40%, with 10% undecided, a 10-point spread will occur on election day only if undecideds split equally (i.e. a 55% to 45% outcome). Since most of the 10 points in the undecided category are likely to go to the challenger, polls are a lot closer than they look ? 50% to 40% is likely to become 52% to 48%, on election day. If a poll is a mirror of public opinion, think of an incumbent poll as one in which objects are closer than they appear.
An incumbent leading with less than 50% (against one challenger) is frequently in trouble; how much depends on how much less than 50%. A common pattern has been for incumbents ahead with 50% or less to end up losing. Final polls showing losing incumbents ahead are accurate. The important question is whether results are reported with an understanding of how undecideds decide
Incumbent Races: Closer Than They Appear