New challenges for telephone survey research in the twenty-first century.

Telephone surveys are critical for examining cross-sectional characteristics of population subgroups, tracking trends in prevalence of conditions and risk behaviors over time, identifying risk factors associated with multiple health conditions, and assessing the effects of interventions. Technology has aided telephone research through advances such as computer-assisted telephone interviewing. However, technology such as answering machines and caller ID has contributed to declines in response rates and has increased costs of conducting telephone surveys. The exponential increase in cell phone utilization presents a challenge to the tradition of random digit dial (RDD) surveys of households. Because telephone surveys are used by other industries such as marketing and public opinion polling, the marketplace may help drive innovation and adaptation. Cell phones have made telephone communication an even greater part of the everyday culture and could make potential telephone survey respondents even more accessible to public health researchers.