It has become a recurring refrain among some Republican pundits and observers each time a new poll shows President Obama or downballot Democrats doing well: Check the party composition.
Critics allege that pollsters are interviewing too many Democrats — and too few Republicans or independents — and artificially inflating the Democratic candidates’ performance.
Pollsters counter that the results they are finding reflect slight changes in public sentiment — and, moreover, adjusting their polls to match arbitrary party-identification targets would be unscientific. [cont.]
Steven Shepard, National Journal