Shifting Party Allegiances Are Tricky for Pollsters

… In the last few weeks, Republican figures such as Karl Rove and Rush Limbaugh have questioned polls showing leads for President Barack Obama over Republican nominee Mitt Romney—including, in Mr. Rove’s case, in the opinion section of this newspaper. They say many polls are skewed because far more respondents are identifying themselves as Democrats than as Republicans. …

Pollsters have defended their practices, saying their interest is in producing accurate opinion numbers, not in backing a candidate. “Every pollster I know just wants to get it right, because that’s what their career is based on,” said Cliff Zukin, a political scientist at Rutgers University and former pollster for the Newark, N.J.-based Star-Ledger.

Behind the charges and defenses is an honest disagreement about how to treat party identification, one that has arisen in past races—sometimes when Democrats said there were too many Republicans in survey samples. [cont.]

Carl Bialik, Wall Street Journal