Background check rate (per 100 000 people) after CBC implementation in Delaware, Washington and Colorado
| Long+handgun background checks | Handgun background checks | Long gun background checks | |||||||
| Delaware | Washington | Colorado | Delaware | Washington | Colorado | Delaware | Washington | Colorado | |
| Observed rate of BCs in treated states following implementation* | 372.0 | 410.7 | 583.9 | 195.5 | 239.8 | 323.5 | 176.5 | 170.9 | 260.4 |
| Counterfactual rate of BCs† | 304.2 | 446.3 | 570.0 | 156.7 | 260.6 | 319.5 | 131.8 | 164.3 | 281.0 |
| Absolute difference in BC rate following implementation‡ | 67.8 | −35.6 | 13.9 | 38.8 | −20.8 | 4.0 | 44.7 | 6.5 | −20.6 |
| Estimated % difference in BC rate following implementation§ | 22.3 | −8.0 | 2.4 | 24.8 | −8.0 | 1.3 | 33.9 | 4.0 | −7.3 |
| N states in the donor pool with change ≥treated state (n=29) ¶ | 1 | 3 | 28 | 2 | 9 | 26 | 0 | 9 | 21 |
*Mean background check rate in treated states after policy implementation.
†Mean background check rate in synthetic controls after policy implementation.
‡Mean difference in background check rate between the treated states and their synthetic control after policy implementation.
§Percentage difference in background checks rate in reference to BC rate of the synthetic controls after policy implementation.
¶Results from the permutation test, measured as the postintervention RMSPE/preintervention RMSPE.
BCs, background checks; CBC, comprehensive background checks; RMSPE, root mean square prediction error.