Table 3.

Simulation results for path c′, the direct effect of treatment on outcome (population value = .2).

	All confounders			Half of confounders			No confounders
	b = .7	b = .5	b = .3	b = .7	b = .5	b = .3	b = .7	b = .5	b = .3
N = 100
Mean	0.171	0.190	0.190	0.134	0.153	0.138	0.001	0.020	0.006
Bias	−0.029	−0.010	−0.010	−0.066	−0.047	−0.062	−0.199	−0.180	−0.194
Rel. Bias	−0.143	−0.048	−0.048	−0.332	−0.236	−0.309	−0.997	−0.899	−0.969
SD	0.216	0.221	0.221	0.231	0.236	0.242	0.270	0.273	0.290
MSE	0.048	0.049	0.049	0.058	0.058	0.062	0.112	0.107	0.121
N = 250
Mean	0.197	0.186	0.186	0.156	0.145	0.146	0.009	−0.003	−0.002
Bias	−0.003	−0.014	−0.014	−0.044	−0.055	−0.054	−0.191	−0.203	−0.202
Rel. Bias	−0.015	−0.070	−0.070	−0.219	−0.275	−0.269	−0.956	−1.017	−1.008
SD	0.131	0.132	0.132	0.147	0.146	0.146	0.174	0.172	0.177
MSE	0.017	0.018	0.018	0.024	0.024	0.024	0.067	0.071	0.072
N = 500
Mean	0.192	0.188	0.188	0.146	0.143	0.150	0.000	−0.004	0.003
Bias	−0.008	−0.012	−0.012	−0.054	−0.057	−0.050	−0.200	−0.204	−0.197
Rel. Bias	−0.040	−0.058	−0.058	−0.270	−0.285	−0.249	−1.002	−1.022	−0.983
SD	0.093	0.096	0.096	0.103	0.106	0.104	0.123	0.122	0.119
MSE	0.009	0.009	0.009	0.013	0.014	0.013	0.055	0.057	0.053
N = 1000
Mean	0.199	0.197	0.197	0.152	0.150	0.149	0.003	0.001	0.000
Bias	−0.001	−0.003	−0.003	−0.048	−0.050	−0.051	−0.197	−0.199	−0.200
Rel. Bias	−0.005	−0.016	−0.016	−0.240	−0.251	−0.255	−0.987	−0.996	−1.001
SD	0.067	0.068	0.068	0.075	0.075	0.074	0.091	0.088	0.089
MSE	0.005	0.005	0.005	0.008	0.008	0.008	0.047	0.047	0.048