Dear Camilla,
Below you will find how you can impose a symmetry and homogeneity
restrictions in the case of a linear version of the AIDS model.
Have a look at the sureg and reg3 help files.
I hope this will help you.
Cheers,
JP
/* Linear Approximate AIDS (LA-AIDS) Model */
/*symmetry restrictions */
constraint define 1 [qBeef]lpp = [qPork]lpb
constraint define 2 [qBeef]lpc = [qChicken]lpb
constraint define 3 [qPork]lpc = [qChicken]lpp
/* homogeneity restrictions*/
constraint define 4 [qBeef]lpb + [qBeef]lpp + [qBeef]lpc + [qBeef]lpt = 0
constraint define 5 [qPork]lpb + [qPork]lpp + [qPork]lpc + [qPork]lpt = 0
constraint define 6 [qChicken]lpb + [qChicken]lpp + [qChicken]lpc +
[qChicken]lpt = 0
global demand1 "(qBeef: w_b lpb lpp lpc lpt lxp co1 si1 t )"
global demand2 "(qPork: w_p lpb lpp lpc lpt lxp co1 si1 t )"
global demand3 "(qChicken: w_c lpb lpp lpc lpt lxp co1 si1 t )"
sureg $demand1 $demand2 $demand3, const(1 2 3 4 5 6) isure
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Camilla Andersson
Sent: Monday, May 08, 2006 3:31 PM
To: [email protected]
Subject: st: symmetry and homogeneity restrictions
Dear all stata users,
My question is simply: How do I impose symmetry and homogeneity
restrictions in stata?
For example if I want to estimate a regression an impose the parameter
restrictions bnk=bkn
and the sum of all betas is equal to 0?
Kind regards
Camilla
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