A reader pointed out this expose of the Ipsos poll on PoliPundit. It’s an excellent piece of work; the bottom line is that polls in which Ipsos is involved, including the recent Newsweek/Ipsos survey, are systematically skewed to favor the Democrats:
The non-Ipsos polls says Bush leads 49.2-45.5. The Ipsos polls say Kerry leads 48.5-45.5.
To see why the Ipsos polls are so unreliable, read the whole thing.
Meanwhile, reader Meg Kreikemeier writes to point out that the most recent Time magazine poll, which shows John Kerry trailing by only one point, oversampled Democrats, just like the current Newsweek poll:
In their 9/21-9/23 poll of likely voters republicans accounted for 36%, democrats accounted for 31% and independents accounted for 25%.