Hello . In order to perform a Cox model, I am supposed to test the proportional hazard hypothesis. On this site https://stats.idre.ucla.edu/other/examples/asa2/testing-the-proportional-hazard-assumption-in-cox-models/ I find this suggestion of code : proc phreg data=uis;
model time*censor(0) = age race treat site aget racet treatt sitet;
aget = age*log(time);
racet = race*log(time);
treatt = treat*log(time);
sitet = site*log(time);
proportionality_test: test aget, racet, treat, sitet;
run; However, if I apply the code with my current variables (where “race” is categorical) I get the error : Variable race should be either numeric or specified in the CLASS statement If I add a line for « class age race treat site ; » I get : Unable to convert a character value to a numeric value Finally the only way to have this program woking is to convert my variable into numeric (white = 1 black = 2 for instance). But is it that I am supposed to do ? I have some doubts here. I have a second question: When I perform the test, I get a (unique) p-value. If I understand correctly it is when the test is concluant (p-value low) that the hypothesis of proportional hazard is not verified right? Thank you very much to who will be able to help me. Best regards.
... View more