YRBSS Methods

See Methodology of the Youth Risk Behavior Surveillance System—2013 for details about how YRBSs are conducted.

For the national, state, territory, tribal government, and local YRBS samples, schools are selected with probability proportional to the size of student enrollment in grades 9-12 and then required classes of students (e.g., English classes) or a specific period of the school day (e.g., 2nd period) are randomly selected to participate. Within selected classes, all students are eligible to participate. See the Methodology of the Youth Risk Behavior Surveillance System for a more detailed description of sampling procedures.

National YRBS data are representative of all public and private school students in grades 9–12 in the 50 states and the District of Columbia. National YRBS data sets are not the aggregate of the state YRBS data sets; the National YRBS uses a separate scientific sample of schools and students.

Most state, territory, tribal government, and local YRBS data that are weighted are representative of all public school students in grades 9–12 in the respective jurisdiction. State, territory, tribal government, and local YRBS data that are not weighted are representative only of the students who completed the survey in the respective jurisdiction.

Weighting is a mathematical procedure that makes data representative of the population from which it was drawn. In the YRBSS, only surveys with a scientifically drawn sample, appropriate documentation, and no evidence of significant nonresponse bias are weighted.

YRBSS data are weighted to adjust for school and student nonresponse and to make the data representative of the population of students from which the sample was drawn. Generally, these adjustments are made by applying a weight based on student sex, grade, and race/ethnicity.