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RE: st: question about heckprob


From   Michael Horowitz <horowitz@fas.harvard.edu>
To   statalist@hsphsun2.harvard.edu
Subject   RE: st: question about heckprob
Date   Wed, 18 May 2005 18:32:48 -0400 (EDT)

Ok maybe I have these things spun around.  Here is a snapshot of what the
data might look like:

dv1 dv2
0   0
0   0
1   0
1   0
1   0
1   1
0   0
0   0
1   1

Should I flip these around?  Do I have the selection variable in the wrong
place or something?  dv1 is the initiation of disputes and dv2 is the
escalation of disputes.  So all cases where dv1=1 don't mean dv2=1.  What
am I doing wrong?

Mike

On Wed, 18 May 2005, jyotsna puri wrote:

> The way I understand it, as of now:
> Within subset dv2==1 (select variable),
> dv1==1 always.
>
> Question: Why is dv1 different from dv2
> within this subset?
>
> My thoughts:
> I know you are trying to find out whether the
> variables that impact selection also impact
> scale (of dispute). Shouldn't you have a dv1 which
> says something like
> dv1 =1 if disputes escalate
> dv1  =0 otherwise.
> Otherwise, there is no way for the specf'n to
> distinguish between the two variables (dv1 and dv2)....
>
> Or is there something here that I am not seeing?
>
>
>
>
>
> Jyotsna (Jo) Puri
> Cell and Voicemail: 201-805-1690
> pjyotsna@hotmail.com
>
>
>
>
> ----Original Message Follows----
> From: Michael Horowitz <horowitz@fas.harvard.edu>
> Reply-To: statalist@hsphsun2.harvard.edu
> To: statalist@hsphsun2.harvard.edu
> Subject: RE: st: question about heckprob
> Date: Wed, 18 May 2005 17:30:51 -0400 (EDT)
>
> Ok.  dv2 is a subset of dv1.  All times dv2 is 1, dv1 is 1, but many of
> the times where dv1 is 1, dv2 is not 1.  Does that make sense?  Should the
> DV be set up differently?
>
>   On Wed, 18 May 2005, jyotsna puri wrote:
>
>  > Michael,
>  > Can you check/send a cross-tab of  dv1 and
>  > dv2, i.e.
>  > table  dv2 dv1
>  > Is dv1 varying within dv2==1? The way you've explained your
>  > variable construction below, it may not be.
>  > Considered using a Tobit?
>  > -Jo
>  >
>  > Jyotsna (Jo) Puri
>  > Cell and Voicemail: 201-805-1690
>  > pjyotsna@hotmail.com
>  >
>  >
>  >
>  >
>  > ----Original Message Follows----
>  > From: Michael Horowitz <horowitz@fas.harvard.edu>
>  > Reply-To: statalist@hsphsun2.harvard.edu
>  > To: statalist@hsphsun2.harvard.edu
>  > Subject: st: question about heckprob
>  > Date: Wed, 18 May 2005 16:34:40 -0400 (EDT)
>  >
>  > To whom it may concern:
>  >
>  > I am trying to run a censored probit model in STATA but I am not sure
> what
>  > the structure of the 2 dependent variables for the heckprob command needs
>  > to look like.  The way my dependent variable is currently set up is that
>  > there is a 0,1 variable of whether or not states enter into disputes and
>  > then a 0,1 variable that only has values for those states that are in
>  > disputes and codes whether they escalated them (what I want to know is
>  > whether the same variables that influence whether or not states select
>  > into disputes also predict whether states will escalate disputes).
>  >
>  > But every time I try to use heckprob I get the following error message:
>  >
>  > Fitting probit model:
>  >
>  > outcome does not vary; remember:
>  >                                    0 = negative outcome,
>  >          all other nonmissing values = positive outcome
>  > r(2000);
>  >
>  >
>  > Could someone please help me and tell me what the structure of a
>  > successful heckprob command is (I looked at the help file already) and
>  > more importantly, how the DVs for it are coded.  The way my code is set
> up
>  > is:
>  >
>  > heckprob dv1 iv1 iv2 iv3 iv4 iv5, sel(dv2 = iv4 iv6 iv7)
>  >
>  > Mike
>  >
>  >
> *******************************************************************************
>  >
>  > Michael Horowitz
>  > 78 Kirkland Street, #1
>  > Cambridge, MA 02138
>  >
>  > *
>  > *   For searches and help try:
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>  > *   http://www.stata.com/support/statalist/faq
>  > *   http://www.ats.ucla.edu/stat/stata/
>  >
>  >
>  > *
>  > *   For searches and help try:
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>  > *   http://www.stata.com/support/statalist/faq
>  > *   http://www.ats.ucla.edu/stat/stata/
>  >
>
> *******************************************************************************
>
> Michael Horowitz
> 78 Kirkland Street, #1
> Cambridge, MA 02138
>
> *
> *   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:
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> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
>

*******************************************************************************

Michael Horowitz
78 Kirkland Street, #1
Cambridge, MA 02138

*
*   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/



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