. 2013 Sep 20;37(7):658–665. doi: 10.1002/gepi.21758

Table 1.

Results from simulation study with independently distributed variants

α₁₂	α₁₃	α₂₃	Mean F	Method	Mean	Median	SD	Mean SE	Coverage	Power
0	0	0	47.3	2SLS	0.196	0.192	0.085	0.085	94.8	65.2
				IVW	0.196	0.192	0.085	0.078	92.6	70.1
				Likelihood	0.200	0.197	0.087	0.082	94.2	69.1
+0.08	+0.1	+0.12	126.9	2SLS	0.199	0.197	0.052	0.051	95.0	98.3
				IVW	0.199	0.197	0.052	0.047	92.6	98.6
				Likelihood	0.200	0.199	0.052	0.050	94.0	98.6
−0.08	+0.1	+0.12	88.1	2SLS	0.198	0.197	0.061	0.062	95.1	78.1
				IVW	0.198	0.197	0.061	0.057	93.0	81.6
				Likelihood	0.201	0.199	0.062	0.060	94.2	80.9
+0.08	−0.1	+0.12	74.4	2SLS	0.198	0.196	0.068	0.067	95.0	86.6
				IVW	0.198	0.196	0.068	0.062	92.9	88.9
				Likelihood	0.201	0.199	0.068	0.065	94.2	88.6
+0.08	+0.1	−0.12	59.6	2SLS	0.197	0.194	0.075	0.075	94.8	92.4
				IVW	0.197	0.194	0.075	0.069	92.8	93.6
				Likelihood	0.201	0.198	0.076	0.073	94.2	93.4
−0.08	−0.1	+0.12	45.8	2SLS	0.197	0.193	0.085	0.086	95.3	28.9
				IVW	0.197	0.193	0.085	0.079	93.3	37.9
				Likelihood	0.202	0.197	0.087	0.084	94.6	35.9
−0.08	+0.1	−0.12	33.1	2SLS	0.196	0.191	0.102	0.102	94.9	46.7
				IVW	0.196	0.191	0.102	0.093	92.7	53.8
				Likelihood	0.203	0.197	0.105	0.100	94.4	52.2
+0.08	−0.1	−0.12	23.0	2SLS	0.190	0.183	0.123	0.124	94.7	64.3
				IVW	0.190	0.183	0.123	0.113	92.8	69.7
				Likelihood	0.201	0.192	0.129	0.121	94.2	68.7
−0.08	−0.1	−0.12	6.6	2SLS	0.172	0.148	0.249	0.244	93.4	2.8
				IVW	0.172	0.148	0.249	0.217	92.1	10.9
				Likelihood	0.221	0.180	0.357	0.285	94.6	5.7

Instrumental variable estimates of causal effect +0.2 from simulated data with and without gene–gene interactions using individual-level data (two-stage least squares method, 2SLS) and summarized data (inverse-variance weighted, IVW, and likelihood-based methods) with mean F statistic, mean and median estimates across 10,000 simulations, SD of estimates, mean SE of estimates, coverage (%) of 95% confidence interval, and power (%) at a 5% significance level