Table 7.2.

Simulation results comparing our approach with Shih’s approach in the sibling study with a binary outcome and a binary exposure. Sample sizes are for achieving a nominal power 90% to detect different relative risks (p₁/p₀) at 0.05 significance level for different correlations ρ. The reference risk p₀ is fixed at 0.1 and ψ₀ = 0. Empirical powers are based on the Wald test.

		Our approach		Shih’s approach		“Actual”
RR	ρ	m	Power (%)	m	Power (%)	m	Power (%)
2.0	0.10	238	90.34	251	91.72	236	90.02
	0.15	225	90.31	238	91.85	220	90.03
	0.20	213	90.93	225	91.95	209	89.96
2.5	0.10	118	90.16	130	92.91	118	90.16
	0.15	112	90.69	124	93.18	109	90.08
	0.20	106	90.70	117	93.37	102	89.96
3.0	0.10	72	90.05	84	93.67	72	90.05
	0.15	68	89.75	79	93.90	68	89.75
	0.20	65	90.36	75	93.88	64	90.00