"
There is much to criticize about Rasmussen's methods. All polls are conducted within a 4-hour window, the person who answers the phone (even a child) is sampled, phones that are not answered are not called back, and much more. All of Rasmussen's polls are done by computer; live interviewers are never used. However, other firms that do robopolling such as SurveyUSA and PPP get much more accurate results with no bias, so the problem is not the robopolling per se.
Just to look at one methodological issue, if no one answers the phone, Rasmussen picks a different random phone number instead of calling back two, three, four or more times as other pollsters do. Why does this matter? Because
20-somethings (who skew Democratic) are often out, whereas
60-somethings (who skew Republican) are often in.
By not being persistent in finally getting through to a randomly chosen phone number, the sample is inherently biased towards Republicans because they are easier to reach. This may not have been intentional but it is understandable if you want to finish your survey in 4 hours. Nevertheless, cutting corners in the name of speed and cost don't improve accuracy."
http://electoral-vote.com/evp2012/Info/rasmussen.html
http://electoral-vote.com/evp2012/Pres/Maps/Sep25-noras.html (Polls ex. Rassmussen show Obama 347 / Romney 191 today)