Oh sure, I'll trust Rove over statisticians...

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.

Unlike race, gender or age, all demographic traits for which pollsters weight their samples, party identification is considered an attitude that pollsters say they should be measuring. When party identification numbers change, it's an indication of deeper political change that a poll can spot.

"If a pollster weights by party ID, they are substituting their own judgment as to what the electorate is going to look like. It's not scientific," said Doug Schwartz, the director of the Quinnipiac University Polling Institute, which doesn't weight its surveys by party identification.

http://www.nationaljournal.com/2012-presidential-campaign/re...