Table 2.

Simulation Experiment 1: results are based on an analysis using subclassification in which strata are defined by quintiles of the estimated PS. We report the estimated bias, variance, and mean-squared error (MSE) of all possible estimators.

Variables in Propensity Score Model
		X1	X2	X3	X1, X2	X1, X3	X2, X3	X1, X2, X3	None
n=500	$B\widehat{I}AS\times {10}^1$	0.29	6.07	7.96	0.24	0.24	7.93	0.24	5.94
	$V\widehat{A}R\times {10}^1$	0.22	0.14	0.62	0.16	0.71	0.43	0.69	0.39
	$M\widehat{S}E\times {10}^1$	0.23	3.82	6.95	0.17	0.71	6.71	0.70	3.92
n=2500	$B\widehat{I}AS\times {10}^1$	0.28	5.96	7.61	0.29	0.55	7.60	0.56	5.95
	$V\widehat{A}R\times {10}^2$	0.43	0.31	1.02	0.27	1.12	0.87	0.96	0.80
	$M\widehat{S}E\times {10}^2$	0.51	35.82	58.90	0.35	1.43	58.63	1.27	36.16