this reply specifically to joanne garrett:
I have modified your wonderful predxcat to allow graphing of error bars when
there are two xv variables, and for including sd's not ci's (useful for
generating bland-altman-style intervals). i'd be happy to send it to you or
upload it somewhere. it's a little rough, but is a little less restrictive
than your version.
as for ver 8 graphics - they are so slow, i've been using gr7 and
powerpoint.
george hoffman
----- Original Message -----
From: Joanne Garrett
To: [email protected]
Sent: Thursday, April 03, 2003 9:00 AM
Subject: Re: st: predict or adjust after logistic?
predxcat and predxcon use the strandard error of the prediction. I plan
to update these programs to take advantage of the Stata 8.0 graphics as
soon as possible (in otherwords, when I figure out how to do it), and
will post them for anyone who is interested.
Joanne Garrett
"Daniel, Gregory" wrote:
>
> I have just tried using the predxcat command, but I noticed that the
> confidence intervals seem too narrow and are pretty much the same as the
> CI's obtained when using:
>
> Adjust x2 x3 x4, by(x1) pr ci
>
> These CI's are calculated using the standard error from the predicted
index,
> not the predicted probability---correct?
>
>
> Christer wrote:
>
> Check out
> Predxcon or predxcat
> or
> logpred , regpred
> or
>
> The commands at Scott Long's Homepage (http://www.indiana.edu/~jslsoc/)
>
> 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
>
> However, this code does not allow me to predict probabilities,
> by(x1), while keeping the other covariates held constant, as the adjust
> command does.
>
> *
> * For searches and help try:
> * http://www.stata.com/support/faqs/res/findit.html
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
