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. 2021 Mar 9;190(9):1859–1866. doi: 10.1093/aje/kwab056

Table 1.

Simulation Results Comparing Unconditional Logistic Regression and Conditional Logistic Regression When Matching Is Exact

Unadjusted ULR ULR + L ULR + SP Unadjusted CLR
Scenario Inline graphic Estimate Estimate Empirical SE Model SE 95% CI Coverage Estimate Empirical SE Model SE 95% CI Coverage Estimate Empirical SE Model SE 95% CI Coverage
1 2.270 2.203 2.277 0.207 0.205 0.949 2.292 0.209 0.206 0.947 2.277 0.269 0.264 0.950
2 2.270 2.204 2.277 0.207 0.205 0.949 2.293 0.209 0.206 0.947 2.279 0.271 0.264 0.950
3 −1.200 −0.349 −0.793 0.163 0.202 0.479 −1.207 0.264 0.262 0.951 −1.209 0.289 0.282 0.953
4 −1.200 −0.871 −1.028 0.086 0.092 0.541 −1.202 0.100 0.101 0.951 −1.204 0.109 0.109 0.950
5 1.200 1.044 1.115a 0.106 0.110 0.883 1.117b 0.107 0.111 0.887 1.202 0.125 0.124 0.953
5 1.200 1.044 1.202c 0.116 0.115 0.951 1.213d 0.117 0.116 0.950 1.202 0.125 0.124 0.953
6 −1.200 −0.687 −0.831 0.053 0.063 0 −1.195 0.077 0.077 0.951 −1.202 0.083 0.083 0.951

Abbreviations: CI, confidence interval; CLR, conditional logistic regression; L, linear term of the matching factor(s); SE, standard error; SP, restricted cubic spline transformation of the matching factor(s); ULR, unconditional logistic regression.

a ULR + L1: ULR that includes a linear term for Inline graphic and dummy variables for Inline graphic.

b ULR + SP1: ULR that includes a spline function for Inline graphic and dummy variables for Inline graphic.

c ULR + L2: ULR that includes a linear term for Inline graphic and dummy variables for Inline graphic, and their interaction terms.

d ULR + SP2: ULR that includes a spline function for Inline graphic and dummy variables for Inline graphic, and their interaction terms.