[Limdep Nlogit List] elasticities in nl models
William Greene
wgreene at stern.nyu.edu
Tue Jul 29 23:58:51 EST 2008
Philomela. Nothing is wrong. The equal elasticities is a signature
feature of the MNL. The MNL model applies within the branches of a
nested logit model. By forcing the IV parameter to equal 1.0, you
also forced the equal elasticities result across the branches as you
see in your table.
/Bill Greene
----- Original Message -----
From: Philomela at gmx.net
To: "Limdep and Nlogit Mailing List" <limdep at limdep.itls.usyd.edu.au>
Sent: Tuesday, July 29, 2008 9:31:21 AM (GMT-0500) America/New_York
Subject: Re: [Limdep Nlogit List] elasticities in nl models
Dear Bill,
thanks very much for answering my question. sorry for asking again about the elasticities. When I run the following model:
nlogit
;lhs= choice, cset, alti
;choices= tap,public, borehole, other
;tree=A(public,tap), B( borehole, other)
;start=logit
;ivset:(A)=[1.0]
;maxit=1000
;RU2
;model:
U(tap) = asctap + frequ1*frequ1 + frequ2*frequ2 +tapp*price + tsump*sump+
sexp*sexp + ascavai*ascavai + ascemply*ascemply + tlincp*lincp/
U(public) = ascpublic + pubdist1*pubdist1 + pubdist2*pubdist2 + frequ1*frequ1
+ frequ2*frequ2 + wait2*wait2+ pp*price+ psump*sump+ ascavai3*ascavai3+ plincp*lincp/
U(borehole) = ascbore+ bp*price + bsump*sump
+sexp*sexp + ascavai2*ascavai2 + ascball*ascball+ blincp*lincp/
U(other)=0 ;
Effects: price(*)$
I get equal cross elasticities as follows:
Decomposition of Effect Total |
| Trunk Limb Branch Choice Effect|
| Trunk=Trunk{1}
| Limb=Lmb[1|1]
| Branch=A
| * Choice=PUBLIC .000 .000 -2.059 -4.392 -6.450
| Choice=TAP .000 .000 -2.059 4.412 2.353
| Branch=B
| Choice=BOREHOLE .000 .000 2.353 .000 2.353
| Choice=OTHER .000 .000 2.353 .000 2.353
Decomposition of Effect Total
| Trunk Limb Branch Choice Effect|
| Trunk=Trunk{1}
| Limb=Lmb[1|1]
| Branch=A
| Choice=PUBLIC .000 .000 -3.755 7.399 3.644
| * Choice=TAP .000 .000 -3.755 -7.798 -11.553
| Branch=B
| Choice=BOREHOLE .000 .000 3.644 .000 3.644
| Choice=OTHER .000 .000 3.644 .000 3.644
Decomposition of Effect Total |
| Trunk Limb Branch Choice Effect|
| Trunk=Trunk{1}
| Limb=Lmb[1|1]
| Branch=A
| Choice=PUBLIC .000 .000 3.257 .000 3.257
| Choice=TAP .000 .000 3.257 .000 3.257
| Branch=B
| * Choice=BOREHOLE .000 .000 -3.511 -1.544 -5.055
| Choice=OTHER .000 .000 -3.511 13.268 9.757
So for tap and public i get equal cross elasticities. What is wrong?
Thanks so much,Philo
-------- Original-Nachricht --------
> Datum: Mon, 28 Jul 2008 11:58:10 -0400 (EDT)
> Von: William Greene <wgreene at stern.nyu.edu>
> An: Limdep and Nlogit Mailing List <limdep at limdep.itls.usyd.edu.au>
> Betreff: Re: [Limdep Nlogit List] elasticities in nl models
> Philo. The ;Effects: routine in NLOGIT works for all model specifications.
> With respect to a nested logit model, however, keep in mind that you can
> only
> compute effects of attributes on elemental alternatives. Nothing that
> appears
> in any utility functions for branches or higher can be analyzed.
> /Bill Greene
>
> ----- Original Message -----
> From: Philomela at gmx.net
> To: limdep at limdep.itls.usyd.edu.au
> Sent: Monday, July 28, 2008 9:33:48 AM (GMT-0500) America/New_York
> Subject: [Limdep Nlogit List] elasticities in nl models
>
> Dear all,
>
> i want to estimate direct and cross elasticties for a nested logit model.
> Can I use the ;effects command for that or does it need to be modified to
> account for the correlation of alternatives within the same partition?
>
> Thanks very much,
> Philo
> --
> GMX startet ShortView.de. Hier findest Du Leute mit Deinen Interessen!
> Jetzt dabei sein:
> http://www.shortview.de/wasistshortview.php?mc=sv_ext_mf@gmx
> _______________________________________________
> Limdep site list
> Limdep at limdep.itls.usyd.edu.au
> http://limdep.itls.usyd.edu.au
>
>
> --
> Professor William Greene
> Department of Economics
> Stern School of Business
> New York University
> 44 West 4th St., Rm. 7-78
> New York, NY 10012
> http://www.stern.nyu.edu/~wgreene
> 212.998.0876
>
> _______________________________________________
> Limdep site list
> Limdep at limdep.itls.usyd.edu.au
> http://limdep.itls.usyd.edu.au
--
Psssst! Schon das coole Video vom GMX MultiMessenger gesehen?
Der Eine für Alle: http://www.gmx.net/de/go/messenger03
_______________________________________________
Limdep site list
Limdep at limdep.itls.usyd.edu.au
http://limdep.itls.usyd.edu.au
--
Professor William Greene
Department of Economics
Stern School of Business
New York University
44 West 4th St., Rm. 7-78
New York, NY 10012
http://www.stern.nyu.edu/~wgreene
212.998.0876
More information about the Limdep
mailing list