Hello @eugenecs ,   Have a look to this .pdf from SAS Documentation : SAS/STAT® 13.1 User’s Guide The PHREG Procedure https://support.sas.com/documentation/onlinedoc/stat/131/phreg.pdf and search for : ' A Simple Test of Trend in the Hazard Ratio'.   On page 5915, you bump into such a test  which is searching for evidence of an increasing or decreasing trend over time in the hazard ratio , but instead of << time >> you can use another factor.   Thanks, Koen ... View more

The last time I did this was about 15 years ago, and I did it 'by hand' in a DATA step.  So I read through the data, and counted number of incidents, and added up the number of person-years, then at the end I did some math for the confidence interval.  That's definitely an option.  If your data are well structured, it's pretty straight forward.   I would start by heading to lexjansen.com and searching the papers indexed there for "incidence".   I found a few with macros, but also saw that SAS/STAT 12.1 introduced PROC STDRATE, which looks like it will do it: https://lexjansen.com/nesug/nesug12/sa/sa19.pdf https://support.sas.com/resources/papers/proceedings13/423-2013.pdf   ... View more