# Re: st: logistic regression

 From "Sebastian F. Büchte" To statalist@hsphsun2.harvard.edu Subject Re: st: logistic regression Date Mon, 12 Mar 2007 11:59:39 +0100

```Looking one more time at your post I realize that you are most likely
dealing with gene data and SNP stands for "Single Nucleotide
Polymorphism". I have to say I am not familiar with the analysis of
such data but I can somehow remember that one has to be careful when
independence etc.

regards
Sebastian

On 3/12/07, Sebastian F. Büchte <sfbuechte@gmail.com> wrote:
```
```Meena,

so you receive two measures (outcome information) from one
measurement? Do you  consider the two measure as two independet ones?

Regards
Sebastian

On 3/12/07, meena khan <meena_25@hotmail.com> wrote:
> Hi,
> Each individual is only measured once but the independent SNP variable has 2
> measures for each person which is why it grouped in this way. the SNP is
> binary so there are 3 possible combinations for each person (00, 01 or 11)
>
> Thanks
> Meena
>
>
> >From: "Sebastian F. Büchte" <sfbuechte@gmail.com>
> >To: statalist@hsphsun2.harvard.edu
> >Subject: Re: st: logistic regression
> >Date: Mon, 12 Mar 2007 11:25:45 +0100
> >
> >Looking at your example data, your statement "only one variable (SNP)
> >is different in each person" appears to be inconsistent with the
> >presented data (check rows for id = 2).
> >
> >I would help a lot to understand how your data is generated. Multiple
> >treatments/measurements for a number of subjects? Is this perhaps
> >panel data? ...
> >
> >regards
> >sebastian
> >
> >On 3/12/07, meena khan <meena_25@hotmail.com> wrote:
> >>Hello,
> >>
> >>I have a dataset where all variables are replicated twice for each
> >>subject,
> >>only one variable (SNP) is different in each person:
> >>
> >>ID          SNP     Event    X1         X2
> >>
> >>1             0          0          a          a
> >>1             1          0          a          a
> >>2             1          1          b          b
> >>2             1          1          b          b
> >>
> >>I would like to know if it is correct to cluster by ID in a normal
> >>logistic
> >>regression model? Conditional logistic regression does not work as when I
> >>group it by ID as there is no variation within the groups. The logistic
> >>cluster option seems correct to me when I read the Stata help – it adjusts
> >>the SEs for intragroup correlation which is what I want. I just want to
> >>check if it is right. Thanks
> >>
> >>Meena
> >>
> >>
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> >>
> >
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```
```*
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```