Cell phone users represent the opinions of likely voters

Americans who have traded in their landlines for cell phones have a lot in common with each other, according to a Pew Research Center study.

The majority is unmarried. They tend to be under age 50. And until recently, they were all left out of public opinion polls.

Now that an estimated 14.5 percent of American adults -- according to the study released in May -- are reachable only by cell phone, public opinion research firms are beginning to dial cell phones for the first time to solicit opinions. A 2006 Pew study estimated that 7 percent to 9 percent of adults had only cell phones.

Eric Nielsen, spokesman for Gallup, said the statistical research organization began using cell phones in its daily polls in January.

"It'll be a permanent fixture. It's definitely the trend, and we see cell phone-only as maybe in the 10 to 15 percent region," Nielsen said. "The landline coverage is going down just as fast as the cell phone is going up. It will have to be a fixture."

The Pew study found that, while a growing number of Americans are only reachable by cell phone, their political opinions don't vary significantly from people of the same demographics reachable on landlines.

The same number of participants identified themselves as Democrats or Democratic-leaning -- 53 percent -- in both the cell phone-only and landline-only groups. Twenty-nine percent of landline-only respondents identified themselves as Republican or Republican-leaning, while 32 percent of cell phone-only respondents said the same.

The study found that some demographics vary. There are higher percentages of cell phone-only users in certain population segments, such as young people and Hispanics.

When Pew doesn't call cell phones, it statistically adjusts the data to make up for missing demographics. Scott Keeter, director of survey research for Pew, said that without cell phone interviews, the center usually reaches just over half the young people it statistically needs.

This could be especially significant in this year's presidential election, Keeter said, because many young people support the presumptive Democratic nominee, Barack Obama.

"We see this year a very strong relationship between age and support for Obama, or if you want to do it the other way, being older and supporting John McCain," Keeter said. "A survey leaving out young people would have bias against Obama."

Until now, public opinion research firms have used automatic dialing systems to reach all polling subjects. Federal law bans the use of automatic dialing to cellular phones, or any outlet that might charge a user for picking up the call.

To get around that prohibition, Keeter said the center has employees randomly dial cell phone numbers.

Interviewing a cell phone user is about twice as expensive as interviewing a landline user, Keeter said, because the center offers reimbursement for minutes. It also takes more time -- and therefore labor costs -- because a cell phone user is more likely to be under age 18, meaning it often takes longer for an employee to reach a subject who is eligible to participate.

Unlike Gallup, Pew does not poll cell phone users daily. Keeter said that the center has included cell phones in six or seven surveys since 2006.

In the past, pollsters have screened out a lot of young people in an effort to represent the opinion of likely voters, because voter turnout for young people is often low, said Jeanne Zaino, assistant professor of political science and international studies at Iona College in New Rochelle, N.Y.

"I really think it's important to stress that, this time around, young people have made a huge difference," Zaino said. "You look at the Iowa caucus. You've got to think that Iowa really, really is important to what now is becoming (Obama's) formal nomination. They have been going out to vote this time around."

Zaino said that in a close election, such as the 2000 presidential race, small behavioral differences matter.

"Then, these kinds of small, cell phone-only, non cell phone-only, they're what can make a difference in polling," she said.

(Distributed by Scripps Howard News Service, http://www.scrippsnews.com)