Did you figure this out ever? If so, could you paste your solution / options that you used? Thanks ... View more

Reb, I don't do these sorts of analyses, but might offer some suggestions. perhaps you can do it with GLIM or GLIMMIX.  When I did a Google search for the title of your request, there are some detailed reference for how to do them using those procedures.  These procedures are part of SAS/Stat, so you probably have them. look at the documentation for SAS/Genetics if you have it. Doc Muhlbaier Duke ... View more

Thanks. I'll look into that. A is infection status (control/infected) and B is time in study (early/late) A and B dont make sense if considered alone in this model so it is the interaction that is most important - this ends up comparing control/infected early in study and control/infected late, so stratifying on time in study (B) is feasible. Will that work even though i have a clustering factor of farm (so an ID Farm statement) in the model? I hadnt considered that some PH assumptions make the test more conservative. How would i know if this is the case with this violation? Message was edited by: reb ... View more

Not sure if this is the right way, but i got the survival outputs of the analysis to be entered into a data table and could read off the 75%, 50% and 25% figures for each factor there. ... View more