. Author manuscript; available in PMC: 2011 Feb 6.

Published in final edited form as: J Stat Comput Simul. 2009 Oct 1;79(10):1245–1257. doi: 10.1080/00949650802255618

Table 2.

Comparison of imputation methods for the Kaplan–Meier estimator with heavy interval censoring.

Imputation	Years after HIV infection
	2.5	5	7.5	10
	S(t) = 0.9394	0.7788	0.5698	0.3679
	Bias ×10²
EXACT	0.00 (0.05)	−0.05 (0.05)	0.01 (−0.02)	−0.16 (−0.07)
RIGHT	18.85 (13.92)	21.31 (16.85)	18.97 (15.63)	14.23 (11.98)
MID	−0.22 (−3.30)	0.26 (−11.55)	−0.65 (−21.11)	−1.59 (−25.46)
MEAN	−0.15 (−2.17)	0.02 (−4.71)	−1.12 (−7.29)	−1.99 (−7.61)
MEDIAN	0.43 (−0.95)	0.09 (−2.63)	−1.26 (−4.62)	−2.28 (−5.08)
MODE	2.29 (2.75)	0.89 (1.37)	−1.35 (−1.24)	−2.95 (−3.13)
RAND	2.42 (0.43)	1.16 (−2.73)	−1.02 (−6.18)	−2.91 (−7.91)
MI	2.44 (0.54)	1.12 (−2.77)	−1.15 (−6.27)	−2.87 (−8.01)
	MSE ×10²
EXACT	0.03 (0.03)	0.09 (0.09)	0.14 (0.13)	0.13 (0.12)
RIGHT	3.65 (2.02)	4.68 (2.97)	3.73 (2.57)	2.12 (1.54)
MID	0.03 (0.12)	0.08 (1.38)	0.14 (4.52)	0.16 (6.58)
MEAN	0.03 (0.07)	0.09 (0.30)	0.15 (0.67)	0.18 (0.72)
MEDIAN	0.03 (0.04)	0.09 (0.17)	0.15 (0.36)	0.19 (0.41)
MODE	0.10 (0.15)	0.12 (0.27)	0.19 (0.46)	0.25 (0.62)
RAND	0.10 (0.03)	0.10 (0.16)	0.15 (0.51)	0.22 (0.77)
MI	0.08 (0.02)	0.08 (0.14)	0.12 (0.50)	0.19 (0.75)
	Coverage probability of 95% EBCI
RIGHT	0.0 (0.0)	0.0 (0.1)	0.1 (0.9)	1.2 (5.1)
MID	91.7 (22.8)	94.7 (0.1)	92.3 (0.0)	90.7 (0.0)
MEAN	97.8 (70.2)	96.3 (62.3)	93.6 (47.8)	90.2 (45.4)
MEDIAN	99.2 (94.6)	97.6 (86.2)	94.0 (76.1)	90.6 (72.0)
MODE	96.3 (99.7)	99.0 (99.8)	98.0 (99.2)	93.3 (98.5)
RAND	89.7 (98.9)	97.3 (85.2)	95.3 (56.5)	88.3 (38.6)
MI	74.3 (93.8)	94.6 (81.8)	92.2 (51.4)	84.4 (33.1)

Note: Numbers not in parenthesis are based on G_A setting; numbers in parenthesis are based on G_B setting. Sample size n = 200, 1000 simulated data sets, and 1000 bootstraps per simulated dataset.