Idaho Behavioral Risk Factor Surveillance System

The Behavioral Risk Factor Surveillance System (BRFSS) is a public health surveillance program developed and partially funded by the federal Centers for Disease Control and Prevention (CDC). The BRFSS is designed to provide state and sub-state estimates of the prevalence of chronic disease, injury, health conditions, and health-related behaviors associated with the major causes of death and disability. Idaho has worked with CDC to conduct the BRFSS since its inception in 1984. The BRFSS has grown to include every state, the District of Columbia, Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, the Federated States of Micronesia, and Palau.The Idaho BRFSS is funded in part by the Centers for Disease Control and Prevention and administered via a cooperative agreement with the Idaho Department of Health and Welfare. The contents of this site are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention.

Data Collection: The Idaho BRFSS used random-digit-dialed (RDD) surveys of landline and cellular telephone users who were aged 18 or older. Landline and cellular telephone numbers were sampled using disproportionately stratified sampling (DSS); the state's seven public health districts were defined as strata. For each landline household contacted, one adult was randomly selected for interviewing from among all adults living in the household. Cellular telephone users were considered primary users of their phone numbers and interviewed directly.The survey instrument was a questionnaire comprised of three parts. A core component included questions standardized by CDC and asked in all states. An optional module component included questions standardized, edited, and evaluated by CDC and which addressed Idaho’s needs. A state-added component included questions not edited or evaluated by CDC but which addressed Idaho's needs. Each landline or cell phone respondent was asked the full questionnaire.Trained interviewers used computer-assisted telephone interviewing (CATI) software to record responses. Interviews were conducted in either English or Spanish per the respondent's choice.Data Weighting: Ideally, all Idaho adults would have an equal chance of being surveyed and a sample would accurately represent the state's population. Sample design and random chance, however can affect the probability of selection. For example, people with multiple phones were more likely to be called. A sample may not include all population groups proportionately, and some demographic subgroups may have lower response rates. Differences between the sample and the population due to sample design and population factors were accounted for by data weighting. A brief introduction to survey data weighting is available from the American Association of Public Opinion Research (AAPOR) (1). In 2011, the BRFSS implemented a new weighting method known as raking or iterative proportional fitting. Raking improved the accuracy of BRFSS results by accounting for cell phone surveying and adjusting for a greater number of demographic differences between the survey sample and the statewide population. Raking replaced the previous weighting method known as post-stratification and is a primary reason why results from 2011 forward are not directly comparable to 2010 or earlier. The 2011 data should be considered a new baseline for future comparisons. A summary of changes to the 2011 BRFSS methodology is available online from CDC (2). A more detailed report on the changes in BRFSS methodology and the effects on subsequent BRFSS estimates is presented by Pierannunzi, et al. (3).Data Limitations: Errors can result from BRFSS data being self-reported, e.g., certain behaviors may be underreported (4). Error may result when a sample deviates from the population. Additional errors may occur due to the population from which the sample is drawn. To be cost effective, the sample was limited to adults aged 18 and older who were non-institutionalized, lived in a household with a landline telephone or who owned a cell phone, and could communicate in English or Spanish. This excluded people in prisons, housed in medical facilities, those who exclusively spoke a language other than English or Spanish, and others who could not communicate by telephone.The Federal Communications Commission estimated 96.9% of Idaho households had voice telephone service in 2015 (5). With ongoing changes in telephone technology, there has been an increase in households with cellular telephones only. All adults with either landline or cellular telephone service were eligible for participation in the survey.References1. American Association for Public Opinion Research. AAPOR | Weighting.http://www.aapor.org/Education-Resources/For-Researchers/Poll-Survey-FAQ/Weighting.aspx. Accessed October 2017.2. Methodological Changes in the Behavioral Risk Factor Surveillance System in 2011 and Potential Effects on Prevalence Estimates. http://www.cdc.gov/surveillancepractice/reports/brfss/brfss.html. Accessed October 2017.3. Pierannunzi C, Town M, Garvin W, Shaw FE, Balluz L. 2012. Methodologic Changes in the Behavioral Risk Factor Surveillance System in 2011 and Potential Effects on Prevalence Estimates. Morbidity and Mortality Weekly Report (MMWR). June 8, 2012 / 61(22);410-413. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6122a3.htm. Accessed October 2017.4. Centers for Disease Control and Prevention. June 2016. Comparability of Data: BRFSS 2014. https://www.cdc.gov/brfss/annual_data/2016/pdf/compare_2016.pdf. Accessed October 2017.5. Federal Communications Commission, Wireline Competition Bureau, WCB Releases 2016 Universal Service Monitoring Report - EDOCS. December 2016 https://apps.fcc.gov/edocs_public/attachmatch/DOC-343025A1.pdf. Accessed October 2017.

BRFSS data are used to identify emerging health problems and to develop and evaluate public health programs. BRFSS information is used by the public, the media, health researchers and clinicians, and policy makers such as public health officials and legislators. For certain state and national objectives, the BRFSS is the only source of data. BRFSS is unique in providing data enabling state health policymakers to assess their own states’ needs and determine progress toward public health goals.

Yes! The BRFSS program has more data than what is displayed on this dashboard. If you would like to request additional data or learn more about BRFSS, please email Jonas Frankel-Bricker at Jonas.FrankelBricker@dhw.idaho.gov.