Improved composite quantile regression and variable selection with nonignorable dropouts
Improved composite quantile regression and variable selection with nonignorable dropouts
复制标题
改进的复合分位数回归和变量选择,具有不可忽略的丢失
DOI:
10.1142/s2010326322500101
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发表时间:
2021-04
期刊:
影响因子:
--
通讯作者:
Lei Wang
中科院分区:
文献类型:
--
作者:
Wei Ma;Lei Wang
With nonignorable dropouts and outliers, we propose robust statistical inference and variable selection methods for linear quantile regression models based on composite quantile regression and empirical likelihood (EL) that accommodate both the within-subject correlations and nonignorable dropouts. The purpose of our study is threefold. First, we apply the generalized method of moments to estimate the parameters in the nonignorable dropout propensity based on an instrument. Subsequently, the inverse probability weighting and kernel smoothing approaches are applied to obtain the smoothed and bias-corrected generalized estimating equations. Second, we borrow the idea of quadratic inference function to construct the improved EL procedure for nonignorable dropouts. The asymptotic properties of the proposed estimators and their confidence regions are derived. Third, the penalized EL method and algorithm for variable selection are investigated. The finite-sample performance of the proposed estimators is studied through simulation, and an application to HIV-CD4 data set is also presented.