Table 7.
Difference-in-Differences Estimates for Overdose Deaths per 100,000.
| Panel A: State and Time Fixed Effects | |||||
|---|---|---|---|---|---|
| (1) | (2) | (3) | (4) | (5) | |
| Opioids | Prescription Opioids | Prescription Opioids Only | Illicit Opioids | Illicit Opioids Only | |
| PMCL | −0.933* (0.495) | −0.570*** (0.181) | −0.496*** (0.170) | −0.505 (0.428) | −0.430 (0.388) |
| Counterfactual Mean | 4.935 | 2.376 | 1.800 | 3.086 | 2.509 |
| Implied Percent Change | −18.898 | −23.982 | −27.556 | −16.368 | −17.153 |
| Panel B: + Demographic and Policy Controls | |||||
| PMCL | −0.936 (0.757) | −0.491** (0.230) | −0.435*** (0.161) | −0.469 (0.653) | −0.411 (0.568) |
| Counterfactual Mean | 4.938 | 2.298 | 1.739 | 3.050 | 2.490 |
| Implied Percent Change | −18.950 | −21.386 | −25.001 | −15.380 | −16.515 |
| Panel C: + OxyContin Misuse | |||||
| PMCL | −0.949 (0.769) | −0.495** (0.237) | −0.435*** (0.162) | −0.478 (0.658) | −0.416 (0.570) |
| Counterfactual Mean | 4.952 | 2.302 | 1.739 | 3.059 | 2.495 |
| Implied Percent Change | −19.173 | −21.521 | −25.010 | −15.629 | −16.692 |
Notes:
10%,
5%,
1% statistical significance. Standard errors (adjusted for state-level clustering) provided. We use two-stage difference-in-differences, weighted by population size. Only states east of the Mississippi River are included in the analysis. In the first step, we regress the outcome on state fixed effects, time fixed effects, and covariates using only untreated observations. 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 population 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. The “Counterfactual Mean” is the mean of the outcome for all treated observations after subtracting off the estimated treatment effect. “Percent Change” is the implied percent change of the estimate given the counterfactual mean.