About 4,000 cell phone-only users will soon start receiving calls from the California Health Interview Survey, an effort being closely watched by polling experts across the country who find it difficult to reach people who don't have landlines.
The biannual health study provides data on more than 42,000 of the state's roughly 12 million households and drives recommendations made to the Legislature and governor, said Sandra Shewry, director of the California Department of Health Care Services.
"The implications are that if we do not include people with cell phones 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. "It will introduce some level of bias in our estimates."
Adding cell phones will raise the state health survey's cost by hundreds of thousands of dollars, said Grant. That's in part because the UCLA Center for Health Policy Research, which is conducting the study, decided to pay cell phone users $25 for completing the half-hour survey to reimburse them for their air time, Grant said.
On both landlines and cell phones, people tend to screen messages and rely on caller ID numbers when deciding whether to answer. Surveyors say cellphone-only users are even harder to reach and more reluctant to take calls from unknown numbers because of the cost.
About 11.8 percent of adults live in households that use only cell phones, according to a recent government estimate, up from 3.5 percent at the end of 2003, according to the National Center for Health Statistics.
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.
Some wonder whether adding cell phones to phone surveys will be successful.
Jon Foley, 25, has lived without a landline for three years. A clinical research coordinator, he typifies the younger, cell phone-only demographic that poll takers are trying to reach.
"Just answering the phone, I think, will be the biggest problem," he said.
Foley said he rarely answers numbers he doesn't recognize because "to be quite honest, most of those calls end up being garbage."