A TALE OF SEVERAL POLLS – AT 8:27 P.M. ET:  We reported earlier that President Obama was registering on ly 43% approval in the daily Rasmussen poll.  Now along come two other polls showing him much stronger – a CNN poll has the president at 50%, and an ABC/Washington Post poll says 51% approve.

Why the dramatic differences between Rasmussen and the others? 

It's in the methodology.  Both CNN and ABC/Washington post take their surveys among "all adults," whereas Rasmussen polls only "likely voters," a far more significant sample.  Rasmussen explains the difference here:

It is important to remember that the Rasmussen Reports job approval ratings are based upon a sample of likely voters. Some other firms base their approval ratings on samples of all adults. President Obama's numbers are always several points higher in a poll of adults rather than likely voters. That's because some of the president's most enthusiastic supporters, such as young adults, are less likely to turn out to vote. It is also important to check the details of question wording when comparing approval ratings from different firms.

The method goes far toward determining the result.  Recall that in 1936 Liberty Magazine conducted a telephone poll that predicted that Alf Landon would defeat Franklin D. Roosevelt for the presidency.  The reason the poll was so wildly wrong was that Roosevelt's strength came mostly from the economic classes that didn't have telephones.  Thus, the poll was weighted toward likely Republican voters.

I'd go with Rasmussen.  Elections are decided by voters, not by "all adults."

March 15, 2011