st: re: constraints

[Kit Baum <baum@bc.edu>]

Although cnsreg is useful, it is hardly necessary for Vidya's problem:

"I am trying to estimate an equation similar to this -

constraint define 1 L.wpi+L2.wpi+L3.wpi=1
cnsreg wpi L.wpi L2.wpi L3.wpi L.ygapm L2.ygapm sswpi L.sswpi, 
constraint(1)"

This constraint may be rewritten as b(L3) = 1-b(L)-b(L2)  and merely 
substituted into the equation,

(wpi - L.wpi)   regressed on (L.wpi-L3.wpi),  (L2.wpi-L3.wpi) and the 
rest

which you can estimate with regress, robust.

If you want the coefficient on L3.wpi, calculate it via lincom.

Kit

Kit Baum, Boston College Economics
http://ideas.repec.org/e/pba1.html

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