Date: Thu, 22 Apr 2004 21:23:28 -0700
Reply-To: Bruce Bradbury <BruceBrad@INAME.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Bruce Bradbury <BruceBrad@INAME.COM>
Subject: Re: phreg when individuals are clustered
Content-Type: text/plain; charset=ISO-8859-1
> I am conducting a study on chick survival in sage-grouse and want to
> develop a proportional hazard model. I radio-marked 2-3 individual
> chicks within a family unit. I am trying to figure out the best way to
> analyze the data. Can anyone give me some help.
You can do a fixed-effects partial likelihood estimation using the
/strata option in phreg. This is like adding in a dummy variable for
See chapter 8 in Alison, Paul (1995), Survival Analysis Using the SAS
System; A Practical Guide (He discusses this in the context of
repeated spells, but your problem appears to be similar).