Proc PHREG Multivariate analysis

[sam369]

Hi All,

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

Thanks

Sam

[Reeza]

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...