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Re: st: predict or adjust after logistic?


From   Christer.Thrane@hil.no
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: predict or adjust after logistic?
Date   Thu, 3 Apr 2003 07:57:34 +0200


Greg wrote:

To predict  probabilities and 95% CIs of the predicted probabilities after
a multivariate  logistic model, I have previously used the following
predict  command:

logistic y x1 x2  x3
predict lr_index,  index
predict se_index,  stdp

gen p_hat =  exp(lr_index)/(1 +exp(lr_index))
gen lb = lr_index -  invnorm(0.975)*se_index
gen ub = lr_index +  invnorm(0.975)*se_index
gen plb =  exp(lb)/(1+exp(lb))
gen pub =  exp(ub)/(1+exp(ub))


bysort x1: tabstat  p_hat plb pub



Check out:

Predxcon or predxcat

or

logpred , regpred

or

The commands at Scott Long's Homepage (http://www.indiana.edu/~jslsoc/)


Christer




                                                                                                                                               
                      "Daniel, Gregory"                                                                                                        
                      <GDaniel@healthcore.com>         To:       "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>           
                      Sent by:                         cc:                                                                                     
                      owner-statalist@hsphsun2.        Subject:  st: predict or adjust after logistic?                                         
                      harvard.edu                                                                                                              
                                                                                                                                               
                                                                                                                                               
                      02.04.03 21:54                                                                                                           
                      Please respond to                                                                                                        
                      statalist                                                                                                                
                                                                                                                                               
                                                                                                                                               





Dear  Statalist,



However, this code  does not allow me to predict probabilities,
by(x1), while keeping the other  covariates held constant, as the adjust
command does.  It seems that  keeping the other covariates held constant
while examining the predicted  probabilities individual covariates is
useful.  Is it possible for me  to do that?

Thanks in  advance.

Greg  Daniel


Gregory  Daniel
Manager, Health Outcomes  Research
Health Core, Inc.






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