Fig. 1.

a) Picture of initial set-up for the ABCD on-line TLFB interview. Research assistants fill out the participant identification, session name, number of months measured, session run, and session date. Substances used by the youth (in this case, alcohol, tobacco cigarettes, and smoked cannabis “MJ”) are selected. Remembered events, such as “parents out of town” and “birthday party”, are populated onto calendar to aid recall (also see Fig. 1c). b) Individual Substance Use Events: After the TLFB is set up (Fig. 1a), the research assistant fills out each substance-use event into the on-line TLFB interview by noting the substance used, standard units, and dates of use (repeated dates are allowable). This example demonstrates a recurring event of daily tobacco cigarette use, in the standard unit of two cigarettes per day. c) This picture shows a completed month in the on-line ABCD TLFB interview. Example shows daily tobacco cigarette use (two cigarettes a day; see Fig. 1b), weekend alcohol use (reported in standard alcohol drinks), and intermittent smoked cannabis use (“smoked MJ”, reported in grams).

Note: the fake drug name is blacked-out to protect validity of the instrument.