Copyright © 2012 Liping Zhu. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Imputation is a popular technique for handling missing data especially for plenty
of missing values. Usually, the empirical log-likelihood ratio statistic under imputation
is asymptotically scaled chi-squared because the imputing data are not i.i.d.
Recently, a bias-corrected technique is used to study linear regression model with
missing response data, and the resulting empirical likelihood ratio is asymptotically
chi-squared. However, it may suffer from the “the curse of high dimension” in multidimensional
linear regression models for the nonparametric estimator of selection
probability function. In this paper, a parametric selection probability function is
introduced to avoid the dimension problem. With the similar bias-corrected method,
the proposed empirical likelihood statistic is asymptotically chi-squared when the selection
probability is specified correctly and even asymptotically scaled chi-squared
when specified incorrectly. In addition, our empirical likelihood estimator is always
consistent whether the selection probability is specified correctly or not, and will
achieve full efficiency when specified correctly. A simulation study indicates that
the proposed method is comparable in terms of coverage probabilities.