Youth are administered the ABCD Substance Use module by a trained research assistant on an iPad and all questionnaires were converted for electronic data capture via REDCap (Harris et al., 2009). Parents are also administered three measures (PLUS form, availability of substances, and parental rules about substances) on an iPad using REDCap software. First, youth are introduced to the substance use module, rules of confidentiality are restated, and youth are asked if they have heard of certain substances. At this point, research assistants do not show the youth the iPad screen (see section B for details) in order to reduce potential exposure of novel substances. The rest of the interview utilizes gating, in that certain questions must be answered positively or negatively in order for the youth to receive a follow-up question or measure (e.g., youth are only asked about substances they have heard of and only asked about substance consequences if they have actually used the drug; see Table 1 for gating details for each instrument). Because youth may enter the study with some prior substance use, the baseline
