Behavioral Risk Factor Surveillance System
The Behavioral Risk Factor Surveillance System (BRFSS) is a state-based system of telephone health surveys that collects information on health risk behaviors, preventive health practices, and health care access primarily related to chronic disease and injury. The survey was established in 1984. Data are collected monthly in all 50 states, Puerto Rico, the U.S. Virgin islands, and Guam.
Data collection is conducted separately by each state. The design uses state-level, random digit dialed probability samples of the adult (aged 18 and older) population. All projects use a disproportionate stratified sample design except for Guam, Puerto Rico, and the U.S. Virgin Islands who use a simple random sample design. The questionnaire consists of three parts: (1) a core component of questions used by all states, which includes questions on demographics, and current health-related conditions and behaviors; (2) optional CDC modules on specific topics (e.g., cardiovascular disease, arthritis), that states may elect to use; and (3) state-added questions, developed by states for their own use. The state-added questions are not edited or evaluated by CDC. Interviews are generally conducted using computer-assisted telephone interviewing (CATI) systems. Data are weighted for noncoverage and nonresponse.
More than 350,000 adults are interviewed each year. Adjusted response rates vary by state and in 2009 ranged between 39% and 67%; unadjusted response rates ranged between 19% and 62%, depending on state and survey year.
The BRFSS is conducted independently by each state and therefore methodologies may vary. Pooled national estimates may not take into account these differences and so may differ from estimates obtained using data sources that use methodologies designed to produce national estimates. Also, the BRFSS was not designed county-specific estimates in most states although county-specific estimates may be presented if there are more than 50 respondents in a county.