. Author manuscript; available in PMC: 2013 Dec 1.

Published in final edited form as: Health Serv Outcomes Res Methodol. 2012 Oct 5;12(4):288–301. doi: 10.1007/s10742-012-0101-2

Table 3.

Simulation results for A₁ associated with U₂ (true effect=3)

		Method	Estimate	Abs. Rel. Bias	Std. Error
U₂ is associated with both A₁ and A₂.	Weak association	R-IV	−120.02	4100%	3671
		S-IV	7.18	139%	2.82
		M-IV	6.58	119%	2.65
		Regression	6.27	109%	0.34
	Moderate association	R-IV	−11.09	470%	350.3
		S-IV	8.64	188%	2.41
		M-IV	8.39	180%	2.25
		Regression	6.27	109%	0.36
	Strong association	R-IV	−2.71	190%	502.4
		S-IV	10.84	261%	2.12
		M-IV	10.30	243%	1.98
		Regression	6.27	109%	0.35