My question is on the non popularity of the royston parmar model. I have been observing the industry and the models mostly used for survival analysis. Why is the Royston Parmar model not so popular as compared to the Cox or the AFT survival Models. Could there be any issues around the model or any weakenesses . I was of the view that given the proportional hazard assumption has failed when I used the Cox. The Royston parmar was the closest option which doesnt have a number of assumptions as compared to the other models.