YTS data were collected from randomly selected classes of students in randomly selected public middle (grades 6-8) and high schools (grades 9-12) in 2003, 2005, 2007, 2009 and 2011. In 2013, only middle school students participated in the YTS as high schools participated in the Youth Risk Behavior Survey.

A weight was associated with each questionnaire 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 tobacco use risk behaviors of all regular public school students in grades 6 through 8 and 9 through 12 in the state of Missouri.