Are supply-side drug control efforts effective? Evaluating OTC regulations targeting methamphetamine precursors

Enforcement efforts are the primary approach to reduce illegal drug use in the U.S., but evidence on their effectiveness is mixed. We provide new evidence on the effectiveness of enforcement efforts by using rich administrative records and the staggered implementation of state laws targeting over-the-counter medicines that can be used to produce methamphetamine. We estimate that the regulations reduced the number of methamphetamine laboratories operating in a state by 36%. We find no evidence of changes in methamphetamine consumption or arrests for drug possession, suggesting people were able to find methamphetamine produced elsewhere. Though we find evidence suggesting methamphetamine producers responded to regulation by obtaining precursors from neighboring states that lacked laws, they do not appear to have systematically moved production to neighboring states. This suggests that production shifted over national borders.