Disparate Polling Methods

Via Kaus, Mark Blumenthal at Pollster.com has as much data as he can get on the disparate polling methodologies in use in Iowa. His conclusion...

...the differences in the way pollsters measure "likely caucus goers" in Iowa are huge, not just in how narrowly they define the electorate but in the kinds of voters pollsters select as "likely caucus goers." But these issues are not unique to Iowa. In 2004, 21 states held Democratic primary elections with single digit turnouts (as a percentage of adults), and only New Hampshire had a turnout that topped 20%. Over the next year months, results from hundreds of polls will be released, polls that will set expectations and drive media coverage, and yet those of us that consume the data will know very little about how tightly the pollsters screen and the kinds of voters they select. If we want to be educated poll consumers, we are going to need to do something to change that. We need to push toward greater routine disclosure of methodological details.