Unless you have repeated events per person, you do not need to keep tack of which follow-up belongs to whom.
The likelihood contribution from the two parts is a product. See any textbook on survival anlysis or p. 50 ff. of: http://staff.pubhealth.ku.dk/~bxc/Melbourne/Staff/foils.pdf or another of the zillion of survival/epidemiology lecture notes on the net. Best, Bendix Carstensen ---------------------- Bendix Carstensen Senior Statistician Steno Diabetes Center Niels Steensens Vej 2 DK-2820 Gentofte Denmark tel: +45 44 43 87 38 mob: +45 30 75 87 38 fax: +45 44 43 07 06 [EMAIL PROTECTED] www.biostat.ku.dk/~bxc ---------------------- > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Vegard Andersen > Sent: Thursday, January 13, 2005 12:52 PM > To: r-help@stat.math.ethz.ch > Subject: [R] coxph() and intervening events > > > Hello! > > I am using the coxph() function for counting process data. I want to > include an intervening event as one of my covariates. In > order to do this > I have split the relevant observations in my data at the time of > intervention. But I have not found any way to "inform" > coxph() of the id > of these observations. The result of this is that coxph() > interprets the > split data as extra observations, which is wrong. > Do anyone have a suggestion on how to specify the ID of subjects > experiencing intervening events? > Or maybe other solutions on how to perform a cox regression > including an > intervening event covariate? > > Thanks in advance! > > -- > Best regards, > Vegard Andersen > Institute of Community Medicine > University of Tromso > Tromso, Norway > > [EMAIL PROTECTED] > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read > the posting guide! http://www.R-project.org/posting-guide.html > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html