Behavioral Risk Factor Surveillance System (BRFSS)

The Behavioral Risk Factor Surveillance System (BRFSS) is a large, ongoing health survey conducted by the Centers for Disease Control and Prevention in collaboration with U.S. states and territories. It collects data through landline and cell phone interviews regarding health-related behaviors, chronic conditions, and the use of preventive services among adults. BRFSS is one of the primary sources of state-level public health data in the U.S. helping to track health trends, guide policy decisions, and inform prevention efforts.

Youth Risk Behavior Survey (YRBS) / Youth Tobacco Survey (YTS)

The Youth Risk Behavior Surveillance System (YRBS) is a school-based survey conducted by the Maryland Department of Health (MDH) in collaboration with the Maryland State Department of Education (MSDE), with support from the U.S. Centers for Disease Control and Prevention (CDC) to monitor health-related behaviors among high school students in the United States. It collects data on priority behaviors such as diet, physical activity, mental health, social and interpersonal behaviors. YRBS provides national, state, and local data that help inform interventions aimed at addressing adolescent health.

Statistical Methods

The Behavioral Risk Factor Surveillance System employs a cross-sectional, state-based disproportionate stratified sampling (DSS) design for landlines and simple random sampling design for cell phones, both utilizing random digit dialing. Inclusion criteria include non-institutionalized adults aged 18 years and older who have access to a home telephone or cellphone. Data are collected continuously throughout the year through anonymous random-digit–dialed landline and cellular telephone surveys using Computer Assisted Telephone Interview (CATI) software, available in both English and Spanish. Survey data are weighted using an iterative proportional fitting process (raking), which adjusts for selection probability, nonresponse, and demographic distributions (e.g., age, sex, race/ethnicity, education, and phone ownership). See the CDC's BRFSS page for more details. Reported estimates are weighted percentages with their corresponding 95% confidence interval. Data are suppressed when the denominator is less than 50 or the relative standard error is above 30%.

The Maryland Youth Risk Behavior Surveillance System employs a cross-sectional, school-based, three-stage cluster sampling design. Inclusion criteria include students in middle school (grades 6-8) and high school (grades 9–12) attending public schools. Data are collected biennially through anonymous, self-administered questionnaires completed during school hours, available in both in English and Spanish. Survey data are weighted using raking ratio estimation, or iterative post-stratification to adjust sample totals to known population totals for grade, sex, and race/ethnicity. See the CDC's YRBSS page for more details. Reported estimates are weighted percentages with their corresponding 95% confidence interval. Data are suppressed when the denominator is less than 30 or the numerator is less than 5.

Age Adjustment

The Behavioral Risk Factor Surveillance System uses direct age adjustment to support comparisons across populations with different age distributions. Age-adjusted estimates are calculated by applying age-specific prevalence estimates from weighted BRFSS data to the age distribution of the 2000 U.S. Projected Population using three age groups (18–44, 45–64, ≥65).