Table 2.

Difference-in-differences estimates for opioid shipments.

	Panel A: State and Time Fixed Effects
	Outcome = log(MME Per Capita)
	(1)	(2)	(3)
	Practitioners	Non-Chain Pharmacies	Chain Pharmacies
PMCL	−1.385** (0.549)	−0.321 (0.202)	−0.045 (0.056)
	Panel B: Demographic and Policy Controls
PMCL	−1.350** (0.557)	−0.341 (0.209)	−0.045 (0.060)
	Panel C: OxyContin Misuse
PMCL	−1.334** (0.548)	−0.344* (0.209)	−0.046 (0.059)

Notes:

^*10%,

^**5%,

^***1% statistical significance. Standard errors (adjusted for state-level clustering) provided. Outcomes are derived from the transaction-level ARCOS for 2010–2018. We use two-stage difference-in-differences, weighted by state population. In the first step, we regress the outcome on state fixed effects, time fixed effects, and covariates using only untreated observations. Only states east of the Mississippi River are included in the analysis. We use the estimates to impute the counterfactuals for the treated units. We regress the difference between the observed outcome and estimated counterfactual on whether the state had enacted a PMCL. “Demographic and Policy Controls” include share of the state population that is White, share of Medicare beneficiaries ages 65+, and policy variables. The policy variables are ACA Medicaid expansion, legal and operational medical marijuana dispensaries, recreational marijuana laws, must-access PDMPs, and opioid prescribing guidelines. Panel C includes controls for the interaction of the 2004–2009 non-medical OxyContin use rate with year indicators.