People who use only cellphones -- who researchers say are more likely to be younger, binge drinkers, smokers and without health insurance -- are about to have a say in shaping California healthcare policy.
All they need to do is answer the phone when the state comes calling.
Beginning in September, about 4,000 cellphone-only users will start receiving calls from the California Health Interview Survey. The effort is being widely watched by polling experts across the country, who are finding it harder to reach people in this age of constant connection.
Whether on a landline or cellphone, people tend to screen messages and rely on caller ID numbers when deciding whether to answer the phone. Compounding the problem for surveyors is the growth of cellphone-only users, who are even harder to reach and more reluctant to take calls from unknown numbers because of the cost.
About 11.8% of adults live in households that use only cellphones, according to a recent government estimate -- up from 3.5% at the end of 2003, according to the National Center for Health Statistics, which also supplied the lifestyle data on the group.
These people are generally very different from those who have landline phones, said Scott Keeter, director of survey research for the Pew Research Center.
"They're younger, they are more likely to be racial or ethnic minorities, less likely to be married, less likely to be homeowners -- and all those things are associated with different political or social attitudes," Keeter said.
Under federal law, those conducting surveys are not allowed to include cellphone numbers in their automated dialing lists, so they must manually dial those numbers. Most blocks of phone numbers are separated into cellphone and landline banks.
The laws are designed to help protect cellphone owners from expensive, unwanted telemarketing calls. However, scientific polls such as the state's health survey are excluded from federal "do not call" lists.
The biannual health study, which provides data on more than 42,000 of the state's roughly 12 million households, is used to "drive decision-making and to drive the recommendations we make to the Legislature or to the governor," said Sandra Shewry, director of the California Department of Health Care Services.
If data are inaccurate, a survey paints a nonrepresentative picture of populations, which can in turn be used as the basis for an improper allocation of funds or just bad decisions, she said.
"The implications are that if we do not include people with cellphones only, then we are likely to be underreporting un-insurance rates, and we're likely to underreport smoking prevalence rates in the state," survey director David Grant said. The numbers won't be dramatic, he said, "but it will introduce some level of bias in our estimates."
In May, the American Assn. for Public Opinion Research offered seminars at its annual convention to discuss the cellphone-only issue. The group is compiling guidelines for surveying by cellphone.
"In the next five years, the whole landscape will change," said Cliff Zukin, professor of public policy at Rutgers University and a former president of the American Assn. for Public Opinion Research. "We're going to have this problem.... That's not going to go away; that problem is going to get worse."
However, some wonder whether adding cellphones to phone surveys will really work.
Jon Foley, 25, has lived without a landline phone for three years. A clinical research coordinator who lives on the Westside, he typifies the younger, cellphone-only demographic that poll takers say they are trying to reach.
"It's an important demographic to tap into; I just think there are logistical barriers," he said. "Just answering the phone, I think, will be the biggest problem."
Foley said he rarely answers numbers he doesn't recognize because "to be quite honest, most of those calls end up being garbage."
Through the early 1970s, most polls were done face to face or by mail. After a 1978 paper by Joseph Waksberg called "Sampling Methods for Random Digit Dialing" advocated a more efficient and less costly survey method, many companies began switching to polling by phone. By the 1980s, most organizations were using random-digit dial telephone polling.
Adding cellphones will boost the state health survey's cost by hundreds of thousands of dollars, in part because the UCLA Center for Health Policy Research, which is conducting the study, decided to pay cellphone users $25 for completing the half-hour survey to reimburse them for their air time, Grant said.
He estimates that pollsters will have to call about 4,000 cellphone users to achieve a completed survey sample of 1,000 because of lower cellphone response rates.
Landline survey takers will not be paid.
Participants will be asked for basic demographic information and issues such as smoking and drinking habits and health insurance status.
"So the only reason to go for these cellphones is, does that group you're missing make a difference?" said J. Michael Brick, vice president of Westat, a private research company.
"As the proportion that you're missing gets bigger, the potential effect on the accuracy also increases."
But that's not to say current surveys do not reflect the overall population.
"They're definitely picking up reflections of the population," said Dowell Myers, a USC professor of urban planning and demography.
"We just don't know what an accurate picture is, and we don't know how fuzzy it is."