Re: [R] predictive accuracy

From: Claudia Beleites <claudia.beleites_at_ipht-jena.de>
Date: Thu, 26 May 2011 15:31:17 +0200

Al,

I'd redo everything and report in the paper that your peculiar predictor was contributing strongly to models that were built without excluding this predictor. This is an important information: your models get "confused" by the predictor (I'd consider this a lack of a certain kind of robustness, but I'm not a statistician).

HTH Claudia

Am 26.05.2011 14:42, schrieb El-Tahtawy, Ahmed:
> I am trying to develop a prognostic model using logistic regression. I
> built a full , approximate models with the use of penalization - design
> package. Also, I tried Chi-square criteria, step-down techniques. Used
> BS for model validation.
>
>
>
> The main purpose is to develop a predictive model for future patient
> population. One of the strong predictor pertains to the study design
> and would not mean much for a clinician/investigator in real clinical
> situation and have been asked to remove it.
>
>
>
> Can I propose a model and nomogram without that strong -irrelevant
> predictor?? If yes, do I need to redo model calibration, discrimination,
> validation, etc...?? or just have 5 predictors instead of 6 in the
> prognostic model??
>
>
>
> Thanks for your help
>
> Al
>
> .
>
>
>
>
> [[alternative HTML version deleted]]
>
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-- 
Claudia Beleites
Spectroscopy/Imaging
Institute of Photonic Technology
Albert-Einstein-Str. 9
07745 Jena
Germany

email: claudia.beleites_at_ipht-jena.de
phone: +49 3641 206-133
fax:   +49 2641 206-399

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Received on Thu 26 May 2011 - 13:34:06 GMT

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