The Maseeh Mathematics & Statistics Colloquium Series.

The Maseeh Mathematics & Statistics
Colloquium Series.

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Date and time: Monday, November 30, 2009  3:15 PM
Room: NH 209
Speaker: Lan Wang, School of Statistics, University of Minnesota
www.stat.umn.edu/~lan/
Title: Locally Weighted Censored Quantile Regression

Abstract: Censored quantile regression offers a valuable supplement to Cox proportional hazards model for survival analysis. Existing work in the literature often requires stringent assumptions, such as unconditional independence of the survival time and the censoring variable or global linearity at all quantile levels. Moreover, some of the work use recursive algorithms making it challenging to derive asymptotic normality. To overcome these drawbacks, we propose a new locally weighted censored quantile regression approach that adopts the redistribution-of-mass idea and employs a local reweighting scheme. Its validity only requires conditional independence of the survival time and the censoring variable given the covariates, and linearity at the particular quantile level of interest. Our method leads to a simple algorithm that can be conveniently implemented with R software. Applying recent theory of M-estimation with infinite dimensional parameters, we establish the consistency and asymptotic normality of the proposed estimator. The proposed method is studied via simulations and is illustrated with the analysis of an acute myocardial infarction dataset. (This is joint work with Dr. Huixia Judy Wang form Department of Statistics, North Carolina State University)