“…More recent studies distinguish between voluntary and mandatory access PDMPs, and provide more definitive evidence that the latter reduced prescription opioid misuse (Ali et al, 2017;Buchmueller and Carey, 2018;Deiana and Giua, 2018;Bao et al, 2018;Grecu et al, 2019;Mallatt, 2019Mallatt, , 2020bKaestner and Ziedan, 2019;Wen et al, 2019;Ziedan and Kaestner, 2020). For example, Grecu et al (2019) show that, following adoption of a mandatory PDMP, the number of admissions to substance use disorder treatment related to opioid use decreases by 20 to 25 percent, although reductions only emerge two years post-policy.…”