On Mon, 27 Aug 2007, Riccardo (Jack) Lucchetti wrote:

>> On Fri, 24 Aug 2007, Franck Nadaud wrote:
>> 
>>> I would like to know if it is possible in system estimation to
>>> recover all the coefficients and standards errors, because i
>>> have to compute the AIDS elasticities.

Ok, folks, attached you will find a script and a dataset to replicate the 
AIDS example for SAS that you can find at

http://support.sas.com/rnd/app/examples/ets/aids/index.htm

and

http://support.sas.com/rnd/app/examples/ets/elasticity/index.htm

Please note:

1) you need CVS gretl for this. 1.6.5 will not do. I haven't tested the 
windows snapshot.

2) A few things are hardwired to replicate the above example. With a bit 
of work, though, this script could be turned into a proper function for 
general AIDS systems.

3) I used a different formula for price elasticities than the one in the 
SAS example. Differences are minor.

4) In principle, one may want to compute a standard error for the 
estimated elasticities via the delta method. I couldn't be bothered, but 
after system estimation the $vcv accessor is there if any of you feels 
like having a go at this (Franck?).



Riccardo (Jack) Lucchetti
Dipartimento di Economia
Università Politecnica delle Marche

r.lucchetti(a)univpm.it
http://www.econ.univpm.it/lucchetti

Attachment: aids.gdt
Description: Binary data

Attachment: aids.inp
Description: chemical/gamess-input

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