Cox-Aalen Model in Survival Analysis

The cox proportional hazards model is most popular and widely used for modeling censored survival data. the cox model has an important assumption that hazard rates are proportional and constant over time. in the case of violating the proportionality assumption the additive hazards models are useful alternative to proportional models. the additive model assumed that the hazard rates may change with time. nevertheless in some cases, some of the covariates may constant but the others may not. the cox-aalen model is the best model to combine both kinds of covariates in the same model. in this study mainly the cox-aalen model has been considered and the model has been illustrated with real data.