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Re: st: scoring system using marginally significant predictors


From   Marcos Vinicius <bioestatistico@inbox.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: scoring system using marginally significant predictors
Date   Thu, 14 Mar 2013 09:50:52 -0800

Internal validation was performed using bootstrap

> -----Original Message-----
> From: dspady@ualberta.ca
> Sent: Thu, 14 Mar 2013 11:39:27 -0600
> To: statalist@hsphsun2.harvard.edu
> Subject: Re: st: scoring system using marginally significant predictors
> 
> Did you split your population and test the prediction based on one half,
> against the other (unpredicted) half.  Just depending on statistics to
> provide a scoring system, rather than also maybe using biologically
> plausible factors (e.g. sex, age staging etc) even if not statistically
> significant seems to me not a good approach.
> 
> Don
> On 2013-03-14, at 11:26 AM, Marcos Vinicius <bioestatistico@inbox.com>
> wrote:
> 
>> Hello ,
>> I would like  to share a strategy and have your opinion.
>> Backward elimination was used to reach the final multivariate  logistic
>> regression model using p<0.10 as entry and stay level  From the final
>> model  We then created a weighted scoring system by rounding all
>> regression coefficients up to the nearest integer (ie, the smallest
>> integer greater than the estimate). This method was based on the beta
>> coefficients
>> Once the final model was defined, we created integer weights for each
>> variable. We calculated these weights by multiplying the model
>> coefficients by 10.As like the article below we considered the
>> statistically significant predictors and also the marginally significant
>> predictors (0.05<p<0.10 ) to determine the scoring system.
>> 
>> Is it ok or the scoring system should be strictly derivated using  only
>> statistically significant predictors?
>> Thanks,
>> Ann Thorac Surg. 2008 Jun;85(6):1938-45. doi:
>> 10.1016/j.athoracsur.2008.03.014.
>> Preoperative prediction of the occurrence and severity of complications
>> after esophagectomy for cancer with use of a nomogram
>> Thanks,
>> Vinicius
>> 
>> ____________________________________________________________
>> FREE 3D MARINE AQUARIUM SCREENSAVER - Watch dolphins, sharks & orcas on
>> your desktop!
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>> 
>> 
>> 
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> 
> Donald Spady
> 
> --
> dspady@ualberta.ca
> 
> 
> 
> 
> 
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