The Behavioral Risk Factor Surveillance System (BRFSS) is the largest continuously conducted health survey system in the world, with more than 400,000 American adults participating each year. The BRFSS was established in 1984 by the Centers for Disease Control and Prevention (CDC). Indiana was one of the 15 states that participated since its inception. By 1993, all states and several U.S. territories had implemented the BRFSS. The Indiana Department of Health (IDOH) is responsible for collecting this vital information for our state so we all can know more about the health status of Hoosiers.

What is a Behavioral Risk Factor?

Every day, people make decisions that impact their health. Some behavioral risk factors that can impact a person’s health include poor eating and sleeping habits, substance abuse, smoking cigarettes, being physically inactive, and not obtaining immunizations or routine medical care. These are shown to lead to a variety of poor health outcomes, such as illness, injury, or even premature death. Using the BRFSS survey to track these behaviors supports the efforts of public health professionals in their development of effective health interventions to address them.

Indiana uses information from the BRFSS to:

• Learn more about critical or emerging health issues.
• Identify potential areas of disparity in terms of health-related outcomes.
• Help various nonprofits around the state plan interventions for people diagnosed with or at risk for specific conditions such as arthritis, cancer, diabetes, and heart disease.
• Produce educational materials to increase awareness of Indiana's health status.
• Provide policymakers and other decision-makers with data-driven information regarding the health of Indiana residents.
• Assist IDOH program areas and other governmental agencies within Indiana with measuring progress towards achieving their strategic goals.
• Monitor statewide progress toward national Healthy People 2030 objectives.
• Provide metrics to support various grants for IDOH and other health-related organizations, including supplying data to the Robert Wood Johnson Foundation and the 500 Cities Project by CDC so county- and city-level analysis of health outcomes are possible.

BRFSS Methodology

Sampling

The BRFSS is a telephone-based survey. Households are selected from blocks of potential phone numbers in an area (including unlisted numbers). One adult in the household is randomly selected to be interviewed. Participants are chosen at random to ensure that the collected data is generalizable to other residents in our state.

Weighting

Once responses are compiled, the CDC analyzes the demographic characteristics of the sample and assigns weights to each of the responses to ensure estimates are reflective of the known population. This weighting allows us to generalize the results of the BRFSS survey to the population as a whole. Because some groups are harder to reach than others, the CDC also weights to compensate for non-selection or non-response bias. In other words, the CDC adjusts for overrepresentation or underrepresentation of certain groups in the sample.

Limitations of the Data

The BRFSS is used to generate prevalence estimates, which are estimates of the true incidence of a particular phenomenon for the population the sample is supposed to represent. Like data compiled from any survey, there are certain limitations associated with the BRFSS data and various ways that error can be introduced into the data.

The reliability of the estimate is directly related to the number of actual unweighted responses for each category or subgroup. If the number of collected responses is small, the estimate may be misleading. Measurement error can occur if a question is not understood by a respondent or if an interviewer states the question in a way that alters the understanding of the question. Non-response bias is always present in any survey. It is impossible to know whether those who refused to participate in the survey would have answered the questions similarly to those who did. Some examples of response error are when a person does not answer a question accurately because they cannot recall the right information or the data collector codes the response incorrectly. Social desirability is a phenomenon where a respondent alters their answer to present a favorable impression to the interviewer or to avoid association with socially stigmatized behaviors.

BRFSS Questionnaire

The questionnaire has four sections:

1. Fixed core sections include standard questions that must be asked by every state/participating territory each year.
2. Rotating core sections include questions that are collected every two, three, or four years by every state/territory. In off years, the rotating core sections may be offered as optional modules.
3. Each year, the CDC offers a selection of optional modules that states can elect to add to their questionnaire. By limiting the number of modules offered each year, the CDC can gather information on specific topics across multiple states/territories.
4. State-added questions are questions of special interest to the state that are not offered as an optional module.

Sometimes there is an emerging core section, which is a small group of questions that are added to the core section. These are usually time-sensitive, topical questions. An example of an emerging core section would be one that collects information on a nationwide outbreak (e.g. H1N1, COVID-19).