Saturday, September 04, 2004

Teixeira To Dems -- Step Back From That Ledge

Ruy Teixeira, who knows a thing or three about polling, weighs in on the Time poll.

The Time poll, conducted 8/31-9/2, has Bush ahead by 11, 52-41 in a 3-way LV matchup that includes Nader. (Time presumably will eventually release the 2-way LV matchup. I'm doubtful we'll ever see RV results.) How plausible is this result?

Well, it's certainly possible that Bush was as far ahead during the convention as this poll suggests. But all other available polls taken during the convention contradict this result.

In an attempt to compare apples to apples, here are Bush-Kerry results from contemporaneous 3-way LV matchups (except Rasmussen, where only a 2-way LV result is available), with Bush's margin in parentheses:

Zogby, 8/30-9/2: 46 Bush-43 Kerry (+3)
ARG, 8/30-9/1: 47 Bush-47 Kerry (tie)
Rasmussen, 8/31-9/2: 49 Bush-45 Kerry (+4)

In this company, 52 Bush-41 Kerry (+11) certainly sticks out. Could it have anything to do with the different dates included in these surveys, even though they are very close? Well, the Rasmussen data are from exactly same period as the Time data (8/31-9/2).

But if you are skeptical of the Rasmussen data, consider the Zogby data. The Zogby data only include an additional day (8/30) when compared to the Time data. But perhaps 8/30 was a very pro-Kerry day since the Republican convention had just started. However, for Zogby and Time to matchup (have Bush leading by 11) for the three days they share, Kerry would have to be leading by about 21 points in Zogby on the day (8/30) they do not share. I rather doubt that is the case.

The simplest hypothesis then is that the Time poll, for this period, is exceptionally pro-Bush and therefore should be viewed with skepticism.