RE: Antwort: st: Adding Up restrictions in LA/AIDS model

["Xia Shang" <xia.shang@ndsu.edu>]

Dear Rich,
Thank you so much for your reply. Yes, you are right, if I dropped
constraint 1 to 7, it works, and no errors were reported. I am a beginner,
so you mean that if I dropped constraint 1 to 7, I can also calculate the
alpha, beta, and gamma of equation 5 by the adding up restrictions, which
are (1-alfa), (0-beta), and (0-gamma)? 

I appreciate your help.

Regards,
Xia 
-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Richard Ochmann
Sent: Friday, November 19, 2010 10:53 AM
To: statalist@hsphsun2.harvard.edu
Subject: Antwort: st: Adding Up restrictions in LA/AIDS model

...
well, in the AIDS, adding-up is fulfilled by definition, right? (see 
Deaton, Muellbauer, 1980, An Almost Ideal Demand System, AER)
this is why - as you mention as well - you can only estimate J-1 equations 
of a system of J equations, which you have done, as i undertand.
if this is the case, you cannot constrain explicitly on the Jth equation, 
which you though try to do in constraint 1 to 7. how should stata find the 
Jth equation? rather, adding-up constraints hold implicitly here when you 
infer the results for the Jth equation residually. thus, you can just drop 
constraint 1 to 7, if i understand your approach correctly.

best, rich

owner-statalist@hsphsun2.harvard.edu schrieb am 19.11.2010 16:57:59:

> Hello all,
> 
> I have a problem about the correct way to make adding up restrictions 
when
> I estimated the LA/AIDS model by SUREG. I estimated 5 commodities so I
> should run 4 equations.  The followings are my codes:
> 
> //adding up//
> constraint define 1 [q1]_cons+[q2]_cons+[q3]_cons+[q4]_cons+[q5]_cons=1 
> //Alfa//
> 
> constraint define 2 [q1]lnp1+[q2]lnp1+[q3]lnp1+[q4]lnp1+[q5]lnp1=0  
>         //Gama//
> constraint define 3 [q1]lnp2+[q2]lnp2+[q3]lnp2+[q4]lnp2+[q5]lnp2=0
> constraint define 4 [q1]lnp3+[q2]lnp3+[q3]lnp3+[q4]lnp3+[q5]lnp3=0
> constraint define 5 [q1]lnp4+[q2]lnp4+[q3]lnp4+[q4]lnp4+[q5]lnp4=0
> constraint define 6 [q1]lnp5+[q2]lnp5+[q3]lnp5+[q4]lnp5+[q5]lnp5=0
> 
> constraint define 7 [q1]lnmp+[q2]lnmp+[q3]lnmp+[q4]lnmp+[q5]lnmp=0 
> //Beta//
> 
> //homogeneity//
> constraint define 8 [q1]lnp1+[q1]lnp2+[q1]lnp3+[q1]lnp4+[q1]lnp5=0
> constraint define 9 [q2]lnp1+[q2]lnp2+[q2]lnp3+[q2]lnp4+[q2]lnp5=0
> constraint define 10 [q3]lnp1+[q3]lnp2+[q3]lnp3+[q3]lnp4+[q3]lnp5=0
> constraint define 11 [q4]lnp1+[q4]lnp2+[q4]lnp3+[q4]lnp4+[q4]lnp5=0
> 
> //symmetry//
> constraint define 12 [q1]lnp2=[q2]lnp1
> constraint define 13 [q1]lnp3=[q3]lnp1
> constraint define 14 [q1]lnp4=[q4]lnp1
> constraint define 15 [q2]lnp3=[q3]lnp2
> constraint define 16 [q2]lnp4=[q4]lnp2
> constraint define 17 [q3]lnp4=[q4]lnp3
> 
> global demand1 "(q1: w1 lnp1 lnp2 lnp3 lnp4 lnp5 lnmp)"
> global demand2 "(q2: w2 lnp1 lnp2 lnp3 lnp4 lnp5 lnmp)"
> global demand3 "(q3: w3 lnp1 lnp2 lnp3 lnp4 lnp5 lnmp)"
> global demand4 "(q4: w4 lnp1 lnp2 lnp3 lnp4 lnp5 lnmp)"
> 
> sureg $demand1 $demand2 $demand3 $demand4, const(1 2 3 4 5 6 7 8 9 10 11
> 12 13 14 15 16 17) isure
> 
> But STATA reports me that
>  (note: constraint number 1 caused error r(303))
> (note: constraint number 2 caused error r(303))
> (note: constraint number 3 caused error r(303))
> (note: constraint number 4 caused error r(303))
> (note: constraint number 5 caused error r(303))
> (note: constraint number 6 caused error r(303))
> (note: constraint number 7 caused error r(303))
> which means the code adding-up constraints have some problems .
> 
> Can anybody point out why they are wrong?
> 
> 
> Thank you very much
> 
> 
> Xia
> 
> 
> 
> 
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