. Author manuscript; available in PMC: 2015 Jan 1.

Published in final edited form as: J Appl Stat. 2013 Sep 5;41(1):10.1080/02664763.2013.834296. doi: 10.1080/02664763.2013.834296

Table 1.

Average treatment effect estimate (Est), average of estimated standard error (SE), and standard deviation of the empirical distribution of treatment effects (Emp SD) for data simulated under the 3 conditions. ZI = zero inflation parameter.

	Unconditional/Unadjusted			Unconditional/Adjusted			Conditional/Unadjusted			Conditional/Adjusted

	Est	SE	Emp SD	Est	SE	Emp SD	Est	SE	Emp SD	Est	SE	Emp SD
Condition 1
Poisson (β₁=.030)	0.201	0.081	0.095	0.275	0.082	0.084	0.280	0.095	0.086	0.280	0.095	0.086
ZI (γ₁ =-.070)	-0.500	0.163	0.172	-0.631	0.180	0.187	-0.679	0.230	0.235	-0.685	0.201	0.207
Condition 2
Poisson (β₁=0)	-0.069	0.092	0.110	-0.011	0.093	0.099	-0.086	0.135	0.122	-0.020	0.106	0.103
ZI (71 =-.070)	-0.560	0.172	0.179	-0.664	0.190	0.195	-0.686	0.253	0.247	-0.692	0.212	0.207
Condition 3
Poisson (β₁ =-.50)	-0.530	0.123	0.138	-0.496	0.123	0.126	-0.598	0.171	0.157	-0.529	0.139	0.134
ZI (γ₁ =-.070)	-0.619	0.204	0.207	-0.681	0.225	0.225	-0.632	0.320	0.302	-0.669	0.257	0.244