<>
The example from the help file is pretty consistent across -version-s and
var orders. Anything specific about your dataset that the list should know
about?
*************
webuse school, clear
heckprob private years logptax, sel(vote=years loginc logptax)
estimates store first
heckprob private logptax years, sel(vote=years loginc logptax)
estimates store second
estimates table first second, se style(oneline)
*************
----------------------------------------
Variable | first second
-------------+--------------------------
private |
years | -.11425967 -.11425967
| .14617174 .14617174
logptax | .35160981 .35160982
| 1.0164852 1.0164852
_cons | -2.7806654 -2.7806655
| 6.9058384 6.9058382
-------------+--------------------------
vote |
years | -.01675109 -.01675109
| .01477355 .01477355
loginc | .9923024 .9923024
| .4430009 .4430009
logptax | -1.278783 -1.278783
| .57175454 .57175454
_cons | -.54582098 -.54582097
| 4.0704183 4.0704182
-------------+--------------------------
athrho |
_cons | -.8663156 -.86631561
| 1.4500281 1.4500279
----------------------------------------
legend: b/se
HTH
Martin
-----Ursprüngliche Nachricht-----
Von: [email protected]
[mailto:[email protected]] Im Auftrag von Chungshik Moon
Gesendet: Mittwoch, 27. Januar 2010 21:05
An: [email protected]
Betreff: st: the order of variables makes difference in 'Heckprob'?
HI Statalist,
I have a question about heckman's selection probit model (heckprob).
It sounds really weird, but it turns out that the outcome changes as the
order of independent variables changes.
That is,
heckprob y1 x1 x2 x3, s(y2 x11 x12 x13)
heckprob y1 x2 x1 x3, s(y2 x11 x12 x13)
have different outcomes for x1 and x2 in both Stata 10 and 11
Even worse is that results vary across the version of Stata. Not only does
each version show the same variable order issue, but even the same model
shows different results across the version.
Please help me out to address this issue.
I also wonder if you have any alternatives to heckprob.
Chungshik Moon
Ph.D. Candidate
Department of Political Science
Florida State University
-Everything is possible for him who believes.
(Mark 9:23)
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