RE: st: multicollinearity with survey data

[Christine Gourin <cgourin1@jhmi.edu>]

thank you!
how do you test for collinearity with survey data, however?
________________________________________
From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] On Behalf Of Steven Samuels [sjsamuels@gmail.com]
Sent: Tuesday, February 22, 2011 1:27 PM
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: multicollinearity with survey data

> On Feb 22, 2011, at 11:55 AM, Christine Gourin wrote:
>
> i have a question about how to check for multicollinearity with survey data. the only information I can find about this is at the site
> http://www.stata.com/support/faqs/res/statalist.html#toask
>
> I am using survey data to investigate variables associated with hospital volume (HVH) as the dependent variable.
> I suspect that teaching status (HOSP_TEACH) is collinear with HVH, as all HVH hospitals are teaching hospitals.
>
> I am not sure how to check for multicollinearity in the full model, which is
>
>
> xi: svy: logistic HVH elective i.agecat flap neckdissection i.procedure i.payor radiation HOSP_TEACH  i.RACE i.comorbidity
>
>
>
> when I run this model, stata drops HOSP_TEACH saying it predicts failure perfectly.
>

This message has nothing to do with multicollinearity.  Multicollinearity concerns the correlations of predictors with each other. This message, refers to the association of outcome and one predictor.  Tabulating HVH against HOSP_TEACH should show you the problem.


Steve

Steven J. Samuels
Consulting Statistician
18 Cantine's Island
Saugerties, NY 12477 USA
Voice: 845-246-0774
Fax:   206-202-4783
sjsamuels@gmail.com





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