Table 3.

Comparison between separate and joint analysis: β₁ = log 2 with event proportion 20%

Size of subcohort	τθ	Separate analysis
		The proposed weight			Borgan at al.’s method
		β̃1	SE	SD	β̂1	SE	SD
100	0·83	0·713	0·244	0·245	0·716	0·263	0·265
	0·11	0·702	0·226	0·236	0·705	0·262	0·270
	0·05	0·700	0·226	0·232	0·710	0·263	0·268
200	0·83	0·703	0·196	0·194	0·704	0·206	0·206
	0·11	0·697	0·186	0·193	0·699	0·205	0·213
	0·05	0·698	0·186	0·187	0·702	0·206	0·209

Size of subcohort	τθ	Joint analysis
		The proposed weight			Kang and Cai’s method
		${\stackrel{\sim }{\beta }}_1^M$	SE	SD	${\widehat{\beta }}_1^M$	SE	SD
100	0·83	0·711	0·243	0·245	0·713	0·262	0·264
	0·11	0·701	0·226	0·235	0·701	0·261	0·267
	0·05	0·700	0·225	0·231	0·707	0·262	0·266
200	0·83	0·703	0·195	0·194	0·703	0·205	0·205
	0·11	0·696	0·186	0·193	0·697	0·205	0·212
	0·05	0·698	0·186	0·187	0·700	0·205	0·209

SE, average standard errors; SD, sample standard deviation.