YRBSS data are collected from randomly selected classes of students in randomly selected public high schools (grades 9-12). A weight is associated with each survey administration to reflect the likelihood of sampling each student and to reduce bias by compensating for differing patterns of non-response. The weighted results may be used to make important inferences concerning health risk behaviors of all regular public school students in grades 9 through 12.

For additional details on the YRBSS methodology, go to the CDC website.