[R-SIG-Mac] Error in GEE models

[stefano iacus]

Please, use the appropriate list, e.g. r-help and you'll get a useful  
answer with higher probability than here.
There is nothing mac specific in your mails
stefano

On 19/set/08, at 01:30, david dav wrote:

> Hi,
> I would like to fit a GLM model with GEE on clustered data.
> I tried to use gee in the GEE package on a twin data set. All cluster
> are of size 2. I removed the missing data first.
>
>> gee(Y ~ X1 + X2,
> +     id = IDENTIF,  family = binomial, corstr = "unstructured",
> +     data =GP)
>
> I get these results :
> Beginning Cgee S-function, @(#) geeformula.q 4.13 98/01/27
> running glm to get initial regression estimate
> (Intercept)         X1M  X2Sans AMP      X2Stim
> -2.4791229   0.4250848  -0.1310666  -0.2151235
> Error in gee(Y ~ X1 + X2, id = IDENTIF, family = binomial, corstr =
> "unstructured",  :
>  NA/NaN/Inf dans un appel `a une fonction externe (argument 2)#in a
> call to an external function would be the translation
> De plus : Warning message:
> In gee(Y ~ X1 + X2, id = IDENTIF, family = binomial, corstr =  
> "unstructured",  :
>  NAs introduits lors de la conversion automatique
>
> geepack does not work any better when the regression gives results
> with SAS version 8 on the same dataset (results are pretty close from
> the results of a naive logistic regression).
> I tried to change the explanatory variables (X1 alone, X2 alone, other
> possible explanatory vairables : no result). I do not find where the
> error comes from.
>
> Thank you for your help.
> David
> Using R2.7.2 and gee version 4.13-13
>
> PS Naive logistic regression give similar results on R and SAS in my  
> case
>
> _______________________________________________
> R-SIG-Mac mailing list
> R-SIG-Mac at stat.math.ethz.ch
> https://stat.ethz.ch/mailman/listinfo/r-sig-mac
>