. Author manuscript; available in PMC: 2014 Jun 10.

Published in final edited form as: Biometrika. 2013 Jun 10;100(3):695–708. doi: 10.1093/biomet/ast018

Table 4.

Type I error and power (%) in separate and joint analyses with event proportion 20%

Size of subcohort	τ_θ	Type I error (β₁ = β₂ = log 2)				Power (β₁ = 0·1, β₂ = 0·7)
		Separate analysis		Joint analysis		Separate analysis		Joint analysis
		P	BR	P	KC	P	BR	P	KC
100	0·83	0·6	0·6	6·3	6·7	49	42	90	78
	0·11	0·8	1·7	5·9	5·9	56	42	83	61
	0·05	1·2	2·1	5·1	5·6	59	43	81	61
200	0·83	0·2	0·3	5·2	5·8	80	72	98	94
	0·11	1·6	1·9	5·4	5·4	77	65	89	78
	0·05	1·8	2·5	5·3	5·4	79	68	90	79

P, the proposed weight; BR, the method of Borgan et al. (2000); KC, the method of Kang & Cai (2009).