Bootstrap Method on Parameter Estimation of Cox Model

ObjectiveTo test the validity of parameter estimation of Cox model with the skewness of independent variables.MethodsTo introduce nonparametric bootstrap method to Cox model and check the difference of their results.ResultsTheir parameter estimation is almost same,but the confidence interval is not,some of the bootstrap down interval is much lower.ConclusionWhen the independent variables are significantly asymmetrical,the confidence interval of the Cox model is not as accuracy as that of bootstrap method.