[R] coxph() and intervening events

[BXC (Bendix Carstensen)]

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
bxc at steno.dk
www.biostat.ku.dk/~bxc
----------------------



> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Vegard Andersen
> Sent: Thursday, January 13, 2005 12:52 PM
> To: r-help at 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
> 
> vegard.andersen at ism.uit.no
> 
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