02-15-2013 10:34 AM
i need to find the risk ratio using phreg model.
i have a dataset with lenth of tretment variable
i want to find the risk ratio for group (<18 months Vs >=24 months) And (18-24 Vs >=24)
Can any one help me with an exampl
02-15-2013 10:41 AM
You need to explain your situation more.
Also, an assumption of PHREG, or a Cox regression model, is proportional hazard over time. So that means that the 'risk ratio' (which I think is the hazard ratio) should be constant?
But its morning and coffee hasn't kicked in yet...