This report compares estimates of youth substance use from the 2002 to 2008 National Survey on Drug Use and Health (NSDUH) with estimates of similar measures from Monitoring the Future (MTF) and the Youth Risk Behavior Survey (YRBS). Substances covered include cigarettes, alcohol, marijuana, cocaine, heroin, ecstasy, and inhalants. Results are shown by grade level, in school/dropout status, month of data collection, and the impact of school absenteeism.