Stata The Stata listserver
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

st: 2 limit tobit in system of demand equations

From   Brunetti Mike <>
Subject   st: 2 limit tobit in system of demand equations
Date   Tue, 3 Jun 2003 12:25:16 -0700 (PDT)

Stata users:

I was wondering if there was a command in stata, or
possibly, an .ado file that can estimate a system of
demand equations with censoring on both sides. 
Specifically, I am trying to estimate a system of 2
demand equations which are censored at 0 and 1. 

I know that I can estimate a single equation using the
“tobit” command but how can I estimate two equations

Here is the model I would like to estimate:
For 3 goods the observed expenditure share on each is:
C, S, H

C* and S* represent the desired expenditure share on
each good:
Where X is a matrix of variables, b1 and b2 are
coefficients, and e1 and e2 are errors.

The system is defined as:
C=	0       if C*<=0
C*    if 0<C*<1
1       if C*>1

S=	0       if S*<=0
	S*     if 0<S*<1-C
	1-C   if S*>1


The equations for C and S are each two limit tobits.
But estimating this system simultaneously is
complicated.  Any help or suggestions would be greatly

Thanks a lot.

Do you Yahoo!?
Yahoo! Calendar - Free online calendar with sync to Outlook(TM).
*   For searches and help try:

© Copyright 1996–2015 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index