Table 2.

Covariate Balance with Four-Group Propensity Score Weights

Variable	Unweighted (U) or Weighted (W)	Standardized Difference, SIM States, Post-SIM	Standardized Difference, Control States, Pre-SIM	Standardized Difference, Control States, Post-SIM
Black	U	0.012	−0.301	−0.302
	W	0.005	−0.009	−0.005
Hispanic	U	−0.089	−0.253	−0.275
	W	−0.005	0.010	0.011
Other race/ethnicity	U	−0.012	−0.027	−0.042
	W	0.001	−0.003	−0.003
Age	U	−0.015	0.051	0.036
	W	−0.001	−0.007	−0.003
Female	U	0.022	−0.005	0.012
	W	0.001	−0.006	−0.006
Medicaid	U	−0.078	0.002	−0.003
	W	−0.004	−0.002	−0.005
Medicare-Medicaid	U	0.053	0.391	0.413
	W	0.004	0.008	0.010
Private insurance	U	0.007	0.085	0.083
	W	−0.001	−0.004	0.000
Uninsured	U	0.122	−0.216	−0.181
	W	0.004	−0.000	−0.002
Other payer	U	0.040	0.031	0.044
	W	0.003	−0.003	−0.003
Length of stay	U	−0.037	−0.100	−0.100
	W	−0.012	0.010	0.006
Emergency Department admission	U	−0.028	−0.045	−0.178
	W	−0.000	0.018	0.016
Comorbidity count	U	−0.133	−0.335	−0.400
	W	−0.009	0.004	0.012

Note: Standardized differences are in comparison to SIM states, pre-SIM implementation.

Source: Authors’ analysis of Healthcare Cost and Utilization Project’s State Inpatient Databases