ppatrawala@INDUCTIS.COM wrote back: > >David >The data does have censored observations, and it is a typical Survival >Analysis problem. >Even if, for arguments sake, my problem is not that of Survival Analysis, i >still am interested in finding out the procedure to calculate the Baseline >Function calculation for time dependent covariates in Proc Phreg. >Perhaps you could post a solution to that effect. It would be greatly >appreciated. > >Regards >Perseus

Okay, I still don't see where you want to go, because:

[1] the point of PROC PHREG is that the proportional hazards model is semi-parametric, with an *unspecified* baseline hazard function; and [2] proportional hazards regression doesn't work right unless you have the proportional hazard assumption being met, and I don't see that you have that; and [3] you may have some discrete regressors and that would lead you from PHREG to the experimental PROC TPHREG.

If you really want survival analysis, instead of time series modeling or queueing theory modeling, I think you should start with PROC LIFETEST, and get a look at the baselines for each of your categories, along with an evaluation of the proportional hazards assumption.

HTH, David -- David L. Cassell mathematical statistician Design Pathways 3115 NW Norwood Pl. Corvallis OR 97330

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