Censored Regression: Local Linear Approximations and their Applications

Abstract

Abstract Various statistical tools are available for modeling the relationship between response and covariate if the data are fully observable. In the situation of censored data, however, those tools are no longer directly applicable. This article provides an easily implemented methodology for modeling the association, based on censored data. The form of the regression relationship will be completely determined by the data; no assumptions are made about this form. Basic ideas behind the methodology are to transform the observed data in an appropriate simple way and then to apply a locally weighted least squares regression. The proposed estimator involves a variable bandwidth that automatically adapts to the design of the data points. That the methodology is very easy to implement is illustrated by several examples, including simulation studies and an analysis of the Stanford Heart Transplant Data and the Primary Biliary Cirrhosis Data. Several theoretical considerations are reflected in the examples. Finally, some basic asymptotic results are established.