Description
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.
Supplier(s)
- Centers for Disease Control and Prevention, Public Health Surveillance Program Office (CDC, PHSPO)
Data Years Available
1984-present; not all states participated prior to 2001.
Periodicity
Annual
Mode
Telephone interview survey.
Selected Content
Issues addressed in the BRFSS include tobacco use, health care coverage, HIV/AIDS knowledge and prevention, physical activity, and fruit and vegetable consumption.
Population covered
U.S. civilian noninstitutionalized population aged 18 years and older residing in households.
Methodology
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.
Response rate and sample size
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.
Interpretation Issues
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.
As with all self-reported sample surveys, BRFSS data might be subject to systematic error resulting from noncoverage (e.g., lower telephone coverage among populations of low socioeconomic status), nonresponse (e.g., refusal to participate in the survey or to answer specific questions), or measurement (e.g., social desirability or recall bias).
Suppression Criteria
Estimates based on fewer than 50 cases or with a 95% confidence interval half-width of 10% or more ((upper CI-lower CI/100) >10) are suppressed.
References
http://www.cdc.gov/brfss and related web pages. Accessed August 12, 2010.
ftp://ftp.cdc.gov/pub/Data/Brfss/2009_Summary_Data_Quality_Report.pdf