Rasmussen Bias Redux
Rasmussen's sample is biased because they're polling on the cheap -- using robocalls, which by law can't dial cell phones, and otherwise cutting corners -- rather than because of some agenda to propagandize for the GOP. The end result, however, is the same: Polls that can't be trusted.
Nate Silver offers more analysis on the Rasmussen polls, which consistently skewed Republican:
Rasmussen’s polls have come under heavy criticism throughout this election cycle, including from FiveThirtyEight. We have critiqued the firm for its cavalier attitude toward polling convention. Rasmussen, for instance, generally conducts all of its interviews during a single, 4-hour window; speaks with the first person it reaches on the phone rather than using a random selection process; does not call cellphones; does not call back respondents whom it misses initially; and uses a computer script rather than live interviewers to conduct its surveys. These are cost-saving measures which contribute to very low response rates and may lead to biased samples.
Rasmussen also weights their surveys based on preordained assumptions about the party identification of voters in each state, a relatively unusual practice that many polling firms consider dubious since party identification (unlike characteristics like age and gender) is often quite fluid.
Rasmussen’s polls — after a poor debut in 2000 in which they picked the wrong winner in 7 key states in that year’s Presidential race — nevertheless had performed quite strongly in in 2004 and 2006. And they were about average in 2008. But their polls were poor this year.
This lends more credence to the view I expressed Wednesday: Rasmussen’s sample is biased because they’re polling on the cheap — using robocalls, which by law can’t dial cell phones, and otherwise cutting corners — rather than because of some agenda to propagandize for the GOP. The end result, however, is the same: Polls that can’t be trusted.