For our outcome variables, we analyzed data from two surveys that used different methods to collect data on marijuana use. The main data source was the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), which used face-to-face interviews (Grant et al., 2009; Grant et al., 2004). Using NESARC data, we examined state-level differences in rates of non-medical marijuana abuse/dependence, and in use. As a secondary data source, we analyzed data from the National Survey on Drug Use and Health (NSDUH). The NSDUH used respondent self-administration procedures to collect data on marijuana use (Grucza et al., 2007; US Department of Health and Human Services). Given the difference between interview and self-administration methodology in the NESARC and the NSDUH, the latter survey provides valuable replication of an important component of our study. We focus on state legalization of medical marijuana up until 2004 because NESARC data were collected primarily during that year.
