. Author manuscript; available in PMC: 2014 Feb 26.

Published in final edited form as: Stat Med. 2013 Jun 3;32(27):4726–4747. doi: 10.1002/sim.5871

Table A.1.

Observational log odds ratio, population log odds ratio (PLOR) and IV estimand compared to two-stage and adjusted two-stage estimates of log odds ratio for unit increase in risk factor from model of confounded association with varying IV effects (Scenario 3). Median estimates across 2 500 000 simulations

Confounded association		β₂ = −1.0	β₂ = −0.6	β₂ = −0.2	β₂ =0	β₂ = 0.2	β₂ = 0.6	β₂ = 1.0
β₁ = 0.4	Observational	−0.088	0.102	0.301	0.400	0.498	0.677	0.826
	PLOR	0.372	0.389	0.389	0.383	0.372	0.340	0.303
	IV estimand	0.375	0.391	0.391	0.385	0.375	0.344	0.307
	Two-stage method	0.376	0.393	0.393	0.387	0.377	0.346	0.308
	Adjusted two-stage	0.377	0.394	0.400	0.400	0.398	0.387	0.366

β₁ = 0.8	Observational	−1.197	−1.066	−0.896	−0.801	−0.700	−0.492	−0.289
	PLOR	−0.539	−0.606	−0.672	−0.700	−0.723	−0.750	−0.750
	IV estimand	−0.525	−0.590	−0.656	−0.685	−0.710	−0.739	−0.739
	Two-stage method	−0.523	−0.587	−0.652	−0.680	−0.705	−0.733	−0.733
	Adjusted two-stage	−0.746	−0.781	−0.800	−0.801	−0.797	−0.778	−0.748