The difficulty of surveying cellphone-only households

Some interesting facts about the difficulty of surveying cellphone users:

Federal law requires that calls to cellphones be hand-dialed; it is illegal to use automatic dialers, which are standard tools for survey and polling firms. Furthermore, a huge fraction of "owners" of cellphone numbers are children ineligible for the health surveys. Once reached, some cellphone users are reluctant to talk at length because they have to pay for incoming calls.

Consequently, it takes roughly nine calls to working cellphone numbers to get one completed survey, compared with five calls to working land-line numbers, said Scott Keeter, a polling expert at the Pew Research Center for the People and the Press, an independent opinion research group. Further, an interview conducted with someone who uses a cellphone costs 2 1/2 times as much as an interview with someone on a conventional phone. In addition to higher labor costs, most surveys now reimburse cellphone users for their minutes, either in cash or through credits to online merchants such as Amazon.com.