Pollsters Struggle to Pin Down the Right Number

As they gauge voter sentiment in this tight presidential race, pollsters face a big challenge: more and more voters hang up on them. So it sounds odd that some pollsters have decided to hang up on more voters.

Yet that is one way survey researchers have adapted to the communications revolution that has upended old methods of measuring which political party is ahead. In the polarized battle between President Barack Obama and Mitt Romney, arcane shifts in polling techniques can have important consequences for the results — and public perceptions of the contest. Bill McInturff, a Republican pollster, and Peter Hart, his Democratic counterpart, who conduct the NBC News/Wall Street Journal poll, proved the point in their latest poll, conducted July 18-22, when they increased the proportion of respondents who rely exclusively on cellphones to 30 percent from 25 percent. To home in on them, the pollsters ended calls answered on cellphones if the respondents said they also had land lines. Their findings affirmed arguments that “cell only” Americans have significantly different, and more Democratic, political views than those with land lines. Over all, the poll showed President Obama leading Mr. Romney by 49 percent to 43 percent — providing a confidence-boosting talking point for Democrats and provoking sharp criticism from Republicans.