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st: predict or adjust after logistic?


From   "Daniel, Gregory" <GDaniel@healthcore.com>
To   "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
Subject   st: predict or adjust after logistic?
Date   Wed, 2 Apr 2003 14:54:21 -0500

Title: Message
Dear Statalist,
 
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
 
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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