Table 1.

Summary statistics for the estimated regression parameters under independent censoring

Proportion censored	Estimated coefficient	Partial		WEE-1		WEE-2		Profile
		Bias	SE	Bias	SE	Bias	SE	Bias	SE	RE
Scenario I: λ0(t) = 2
0%	β̂1	6	133	−1	98	−1	98	−2	98	1.84
	β̂2	5	83	0	65	0	65	−2	65	1.60
30%	β̂1	6	151	−46	136	2	120	1	108	1.98
	β̂2	6	94	−57	90	2	82	4	77	1.50
50%	β̂1	10	171	−113	189	10	157	12	122	1.96
	β̂2	6	112	−125	115	2	98	10	90	1.53
Scenario II: λ0(t) = 2t
0%	β̂1	4	118	0	98	0	98	−1	97	1.45
	β̂2	2	74	0	63	0	63	−1	63	1.40
30%	β̂1	3	132	−21	137	9	121	3	105	1.58
	β̂2	5	89	−28	90	4	80	2	73	1.46
50%	β̂1	6	159	−101	206	10	154	5	118	1.82
	β̂2	8	100	−97	118	6	96	5	79	1.62
Scenario III: λ0(t) = 0.5(t − 2)2
0%	β̂1	6	112	5	104	5	104	5	104	1.17
	β̂2	6	69	5	65	5	65	5	64	1.14
30%	β̂1	10	134	10	143	10	130	9	122	1.21
	β̂2	7	82	0	85	3	80	4	77	1.14
50%	β̂1	9	151	−34	216	7	154	6	134	1.27
	β̂2	7	97	−35	123	7	98	5	88	1.20

Partial, the maximum partial likelihood estimator; WEE-1 and WEE-2, estimators derived by solving U₁(β) = 0 and U₂(β) = 0; Profile, the maximum pseudo-profile likelihood estimator; Bias and ES, empirical bias (×1000) and empirical standard deviation (×1000) of 2000 regression parameter estimates; RE, the empirical variance of the maximum partial likelihood estimator divided by that of the maximum pseudo-profile likelihood estimator.