[R] AFTREG with ID argument

Philipp Rappold philipp.rappold at gmail.com
Fri Feb 5 12:24:26 CET 2010


Dimitris,

thanks for the hint, I'll definitely give it a shot later.

But for now it would be great to understand the aftreg arguments 
first :)

All the best
Philipp

Dimitris Rizopoulos wrote:
> In case this time-dependent covariate is an internal time-dependent 
> covariate (aka endogenous time-dependent covariate), you can use the 
> jointModel() function from package JM, with the option "weibull-AFT-GH" 
> for the 'method' argument.
> 
> For more information you may have a look at: 
> http://rwiki.sciviews.org/doku.php?id=packages:cran:jm
> 
> 
> I hope it helps.
> 
> Best,
> Dimitris
> 
> 
> Philipp Rappold wrote:
>> Dear all,
>>
>> I have some trouble using the "id"-argument with aftreg (accelerated 
>> failure time regression analysis from the eha library).
>>
>> As far as I understand it, the id argument is used to group 
>> individuals together if there are time-varying covariates and the data 
>> is arranged in counting process style.
>>
>> Unfortunately, i cannot figure out how to use the "id"-argument. The 
>> most straight-forward way would be to simply state the grouping 
>> variable, but it throws an error. I've included an example below: the 
>> dataframe for regression is called "test", with the grouping variable 
>> "person".
>>
>>  > test
>>   start end censor person var1
>> 1     0   1      0      1  0.5
>> 2     1   2      0      1  0.4
>> 3     2   3      0      1  0.6
>> 4     3   4      1      1 -0.3
>> 5     0   1      0      2  0.6
>> 6     1   2      0      2  0.7
>> 7     2   3      0      2  0.6
>>
>>  > fit <- aftreg(Surv(start, end, censor)~var1, data=test, id=person)
>> Error in order(id, Y[, 1]) : argument 1 is not a vector
>>
>>  > fit <- aftreg(Surv(start, end, censor)~var1, data=test, 
>> id=test["person"])
>> Error in `[.data.frame`(id, ord) : undefined columns selected
>>
>>
>>
>> What would be the correct way to fit this example model?
>>
>> Thanks + all the best
>> Philipp
>>
>> ______________________________________________
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>> PLEASE do read the posting guide 
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>



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