Confidence Bands for the Median Survival Time as a Function of the Covariates inthe Cox Model

摘要

The proportional hazards model of Cox (1972) specifies that the hazard rate foran individual with covariate vector x is a certain equation where beta sub o is a vector of unknown-regression coefficients and lambda, the underlying baseline hazard rate, is an unknown and unspecified nonnegative function. In most cases where this model is used, interest centers on the estimation of beta sub o. However, it is often also very useful to investigate the effect of the covariates on the median (or some other fixed quantile) of the survival time.