Biomedical Engineering Reference
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bias and variance can be explicitly computed. A comparison of this result
to the asymptotics for F M n shows that the asymptotic variance is the same
in both cases; however, the asymptotic biases are unequal and there is no
monotone ordering between the two. Thus, in some situations the MSLE may
work better than the SMLE, and vice versa. Groeneboom et al. (2010) dis-
cuss a bootstrapped-based method for bandwidth selection but do not provide
simulation-based evidence of the performance of their method. The work in
Groeneboom et al. (2010) raises an interesting question. Consider a practi-
tioner who wants to construct a confidence interval for F(t 0 ) in the current
status model and let us suppose that the practitioner is willing to assume that
F around t 0 is reasonably smooth (say, three times differentiable). She could
either use the likelihood ratio technique from Banerjee and Wellner (2005) or
the smoothed likelihood approach of Groeneboom et al. (2010). The former
technique would avoid bandwidth specification and also the estimation of nui-
sance parameters. The latter would need active bandwidth selection and also
nuisance parameter estimation. In this respect, the likelihood inversion pro-
cedure is methodologically cleaner. On the other hand, because the smoothed
estimators achieve a higher convergence rate (n 2=5 as opposed to n 1=3 obtained
through likelihood-based procedures), the CIs based on these estimators would
be asymptotically shorter than the ones based on likelihood ratio inversion. So,
there is a trade-off here. The n 1=15
faster rate of convergence of the smoothed
MLE will start to show at large sample sizes, but at smaller sample sizes,
bandwidth selection and the estimation of nuisance parameters from the data
would introduce much more variability in the intervals based on the smoothed
MLE. There is, therefore, a need for a relative study of these two procedures
in terms of actual performance at different sample sizes.
Groeneboom et al. (2011) also use kernel smoothed estimators to remedy
the inconsistency of the MLE in the continuous marks model under current
status censoring. They develop a version of the MSLE in this model following
similar ideas as in the above paper: the log-likelihood function for the observed
 
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