"I think religion is going to be at least subliminally an issue in this election," Newport said on the conference call.
While the public has shown growing acceptance over time for black, female, Roman Catholic, and gay candidates, the numbers for Mormons have remained "flat historically," Jones said. When Romney's father, George Romney, ran for the Republican nomination for president, an April 1967 Gallup poll indicated that 17 percent of Americans would not support a Mormon's candidacy.
While question substance is one goal of the call – and a follow-up conversation a day later – another is to make sure the questions asked will prompt a phone conversation of 18 minutes or less. Gallup research indicates that respondents tend to tune out or jump off a call at that point.
Mr. Krosnick of Stanford notes that this preliminary part of the poll process is key because poor question construction can create bias and ultimately influence the data. Surveys that pose agree-or-disagree, true-or-false, or yes-or-no questions typically push people in the affirmative direction, he says.
Other questions are leading. Such as this example Krosnick suggests: "Some people believe that Barack Obama was born outside the United States. How much do you agree or disagree?"
The question sends a signal that the interviewer – or survey sponsor – might have an agenda. A more neutral way to ask would be to also include a mention that others believe Obama was born in the US.
Yet another way to skew results, says Krosnick, is to target respondents who favor a candidate or issue. "If you prefer to slant a poll in a particular direction, then you can make decisions about who to go after and how to go after them," he says. "If a candidate does better in higher socioeconomic status [areas], use more respondents in [those areas]."