Ahmed, Farid E.Vos, Paul W.Holbert, Donald2011-02-042011-05-172011-02-042011-05-172007-02-12Molecular Cancer; 6:15 p. 1-12http://hdl.handle.net/10342/3202The Cox proportional hazards model is the most widely used model for survival analysis because of its simplicity. The fundamental assumption in this model is the proportionality of the hazard function. When this condition is not met, other modifications or other models must be used for analysis of survival data. We illustrate in this review several methodological approaches to deal with the violation of the proportionality assumption, using survival in colon cancer as an illustrative example. Originally published Molecular Cancer, Vol. 6, No. 15, Feb 2007en-USAuthor notified of opt-out rights by Cammie JenningsSurvival modelsColon (Anatomy)--CancerCox proportional hazards modelArticlePMC181054510.1186/1476-4598-6-15