Snapshot of an example timeline used to facilitate recollection and accurate measurement of past substance use
This figure represents the timeline of a participant who is 19 years old, in college, works in a restaurant, and lives on campus. He/she had a prior job as a life guard, and was in a dating relationship from the summer of 2008 to the early spring of 2009. At the end of 2009, he/she used alcohol on a weekly basis and tobacco on a daily basis. The participant used cannabis on a weekly basis during the summers of 2008 and 2009, but not during the school year. He/she used another drug on three occasions in the past two years.