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. Author manuscript; available in PMC: 2015 Oct 1.
Published in final edited form as: Ann Epidemiol. 2014 Aug 12;24(10):747–753. doi: 10.1016/j.annepidem.2014.07.014

Table 2.

Reduced models with correctly specified parameters for adjustment of collider-stratification bias in a cohort (N=100,000) defined by the DAGs in Figures 31 and 41

Trial P(S=1|Y=0,X=0,Z=0) eβSX eβSY eβSYX True
ORYX|z
Biased
ORYX|z,S=1
Bias adjusted
ORYX|z,S-adj
Bias RMSE
A1 0.10 5.0 5.0 1.0 1.01 (0.97, 1.04) 0.59 (0.55, 0.63) 1.01 (0.98, 1.05) 0.0055 0.0182
A2 0.20 5.0 5.0 1.0 1.01 (0.97, 1.04) 0.62 (0.59, 0.65) 1.01 (0.98, 1.05) 0.0019 0.0175
A3 0.50 5.0 5.0 1.0 1.01 (0.97, 1.04) 0.75 (0.72, 0.78) 1.01 (0.97, 1.04) −0.0001 0.0174
A4 0.70 5.0 5.0 1.0 1.01 (0.97, 1.04) 0.83 (0.80, 0.87) 1.01 (0.97, 1.04) −0.0008 0.0174
A5 0.10 0.7 0.7 1.0 1.01 (0.97, 1.04) 1.00 (0.88, 1.14) 1.02 (0.98, 1.05) 0.0067 0.0187
A6 0.10 10.0 0.5 1.0 1.00 (0.96, 1.03) 1.25 (1.12, 1.39) 0.99 (0.96, 1.03) −0.0027 0.0183
A7 0.10 10.0 5.0 1.0 1.00 (0.96, 1.03) 0.44 (0.41, 0.48) 0.99 (0.96, 1.03) −0.0012 0.0181
A8 0.10 10.0 10.0 1.0 1.00 (0.96, 1.03) 0.33 (0.30, 0.35) 0.99 (0.96, 1.03) −0.0018 0.0182
B1 0.10 5.0 5.0 1.0 1.97 (1.90, 2.05) 1.16 (1.09, 1.24) 1.98 (1.91, 2.05) 0.0077 0.0203
B2 0.20 5.0 5.0 1.0 1.97 (1.90, 2.05) 1.22 (1.16, 1.29) 1.98 (1.90, 2.05) 0.0030 0.0190
B3 0.50 5.0 5.0 1.0 1.97 (1.90, 2.05) 1.47 (1.41, 1.53) 1.97 (1.90, 2.05) 0.0000 0.0188
B4 0.70 5.0 5.0 1.0 1.97 (1.90, 2.05) 1.63 (1.57, 1.70) 1.97 (1.90, 2.05) −0.0014 0.0188
B5 0.10 0.7 0.7 1.0 1.97 (1.90, 2.05) 1.99 (1.73, 2.29) 2.01 (1.94, 2.09) 0.0365 0.0410
B6 0.10 10.0 0.5 1.0 1.97 (1.90, 2.04) 2.54 (2.32, 2.78) 1.97 (1.90, 2.05) 0.0062 0.0199
B7 0.10 10.0 5.0 1.0 1.97 (1.90, 2.04) 0.92 (0.85, 0.98) 1.97 (1.90, 2.04) 0.0002 0.0189
B8 0.10 10.0 10.0 1.0 1.97 (1.90, 2.04) 0.82 (0.77, 0.87) 1.97 (1.90, 2.04) 0.0027 0.0191
C1 0.20 5.0 5.0 0.4 1.97 (1.90, 2.05) 1.05 (1.00, 1.11) 1.98 (1.90, 2.05) 0.0023 0.0189
C2 0.20 5.0 5.0 0.8 1.97 (1.90, 2.05) 1.19 (1.13, 1.25) 1.98 (1.90, 2.05) 0.0033 0.0191
C3 0.20 5.0 5.0 2.0 1.97 (1.90, 2.05) 1.29 (1.22, 1.36) 1.98 (1.90, 2.05) 0.0029 0.0190
C4 0.20 5.0 5.0 5.0 1.97 (1.90, 2.05) 1.34 (1.27, 1.41) 1.98 (1.90, 2.05) 0.0031 0.0190
1

Simulated prevalences in the hypothetical population were held constant as follows: P(X=1 | Z=0) = 0.3 and P(Y=1 | X=0, Z=0) = 0.5.