title: Natural experiments in a complex and dynamic environment: the need for a measured assessment of the evidence.
authors.forename: Rosalie Liccardo
authors.initials: RL
authors.lastname: Pacula
authors.forename: Eric L
authors.initials: EL
authors.lastname: Sevigny
mesh_terms: D006801:Humans; D007880:Legislation, Drug; D008385:Marijuana Smoking / Q000331:legislation & jurisprudence*