Hi Rick, I have a related question regarding the computation of CI's for splines in PHREG. I have been successfully using the %est macro described by LinusS_ in this post (https://communities.sas.com/t5/SAS-Health-and-Life-Sciences/How-do-I-plot-the-spline-effect-in-PHREG/td-p/108326 ) However, similar to the SAS graph above in this post, the confidence interval is essentially zero at the reference point, whereas similar code I have tried in R produces a continuous CI that does not approach zero width at the reference point. I am having difficulty finding statistical literature related to the validity of the CI estimation in SAS as opposed to what is produced in R and was wondering if you would be able to provide insight into these different methods of CI computation and whether there is a way to compute CIs in SAS that do not approach zero at the reference point for the spline. Thank you for your consideration and help!
... View more
