Stata The Stata listserver
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

Re: st: RE: -prgen- with a quadratic function


From   Nick Winter <nw53@cornell.edu>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: -prgen- with a quadratic function
Date   Tue, 15 Mar 2005 21:20:58 -0500

Also, my -oprobpr- can do this; it is available from SSC.

--Nick Winter

At 10:03 PM 3/15/2005 +0000, you wrote:
I don't think Scott Long is a member of Statalist.

No matter: your problem should yield to -adjust-
followed by an appropriate graph.

Nick
n.j.cox@durham.ac.uk

Mariano Sana

> Hi Statalisters.  Someone experienced with ?prgen- might be
> able to answer this.
>
> I ran a logit model that has, among its predictor variables,
> AGE and AGESQ.
> The coefficient for AGE is positive and the coefficient for AGESQ is
> negative.  The turning point is at age 79 or so.  I?ve been trying to
> generate a graph that shows how predicted probabilities vary
> by age for a few groups in my analysis.  I used the ?prgen- command from
> the Spostado package.
>
> The graph that I get doesn?t make sense. The probability
> increases nonstop
> and becomes asymptotic to 1 at age 90 or so.
>
> I realize that the problem is that ?prgen- cannot vary the
> value of AGESQ
> as the value of AGE varies.  The default for AGESQ is the
> mean of AGESQ,
> unless I specify another value.  Obviously, I need AGESQ to
> be the square of AGE as AGE varies.
>
> By now I think I have no other solution than running
> ?prvalue- (also from
> the Spostado package) multiple times to get the probabilities
> I need for
> the graph. Or is there any other way? Is this a question for
> Scott Long?

*
*   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/
--------------------------------------------------------
Nicholas Winter                           607.255.8819 t
Assistant Professor                       607.255.4530 f
Department of Government              nw53@cornell.edu e
308 White Hall            falcon.arts.cornell.edu/nw53 w
Cornell University
Ithaca, NY 14853-4601


*
*   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/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index