Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: RE: st: Valid instrument test for exactly identified regression
From
"Schaffer, Mark E" <[email protected]>
To
<[email protected]>
Subject
RE: RE: st: Valid instrument test for exactly identified regression
Date
Wed, 15 Jun 2011 14:32:52 +0100
Justina,
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of
> Justina Fischer
> Sent: 15 June 2011 14:19
> To: [email protected]; [email protected]
> Subject: Re: RE: st: Valid instrument test for exactly
> identified regression
>
> well, validity implies that the exclusion restriction is satisfied.
> At least I learned this in grad school...
True. But it's not testable if the equation is just-identified. You
only have degrees of freedom available for testing if it's
overidentified (hence the name of the test - Eric's point).
> Nevertheless, he needs more and better instruments.
Indeed!
--Mark
> JF
> -------- Original-Nachricht --------
> > Datum: Wed, 15 Jun 2011 14:10:22 +0100
> > Von: "Schaffer, Mark E" <[email protected]>
> > An: [email protected]
> > Betreff: RE: st: Valid instrument test for exactly identified
> > regression
>
> > Justina,
> >
> > I don't think the test you proposed makes sense, to be
> honest. (Maybe
> > you had in mind a test of the exogeneity of the endogenous
> regressor?)
> > But your conclusion - find a second instrument - is sensible.
> >
> > --Mark
> >
> > > -----Original Message-----
> > > From: [email protected]
> > > [mailto:[email protected]] On Behalf
> Of Justina
> > > Fischer
> > > Sent: 15 June 2011 13:56
> > > To: [email protected]
> > > Subject: Re: st: Valid instrument test for exactly identified
> > > regression
> > >
> > > so it was significant at the 10% level ? That's no good.
> > > Try to find a second instrument for decent testing (e.g.a
> quadratic
> > > term of your first instrument) .
> > > JF
> > >
> > > -------- Original-Nachricht --------
> > > > Datum: Wed, 15 Jun 2011 12:45:23 +0000
> > > > Von: [email protected]
> > > > An: [email protected]
> > > > Betreff: Re: st: Valid instrument test for exactly identified
> > > > regression
> > >
> > > > Hi thanks, I've already tried that informally and the IV wasn't
> > > > significant at 95%. But is there a Hansen J-like test I can
> > > do that is more formal?
> > > > Thanks.
> > > >
> > > >
> > > > Sent from my BlackBerry Wireless Handheld Powered by Gee!
> > > from StarHub
> > > >
> > > > -----Original Message-----
> > > > From: "Justina Fischer" <[email protected]>
> > > > Sender: [email protected]
> > > > Date: Wed, 15 Jun 2011 13:34:03
> > > > To: <[email protected]>
> > > > Reply-To: [email protected]: Re: st: Valid
> > > > instrument test for exactly identified regression
> > > >
> > > > well, going back to your econometric textbook you could
> > > test whether
> > > > the instrument is significant when added to the main
> > > regression (exclusion
> > > > restriction) - it should not be....
> > > >
> > > > Justina Fischer
> > > > -------- Original-Nachricht --------
> > > > > Datum: Wed, 15 Jun 2011 10:10:32 +0000
> > > > > Von: [email protected]
> > > > > An: [email protected]
> > > > > Betreff: st: Valid instrument test for exactly identified
> > > regression
> > > >
> > > > > Hi all,
> > > > > I have a model that is exactly identified, so the
> > > xtivreg2 command
> > > > > gives me a zero for the Hansen J statistic.
> > > > > Can you please advise: how do I test the validity of the
> > > IV, that it
> > > > > doesn't correlate with the errors in the structural equation?
> > > > > I know the IV is relevant from the first stage (1st stage
> > > > > F-test, weak-instrument robust inference tests -- all
> reject null at 99%).
> > > > > Thanks!
> > > > > E
> > > > > Sent from my BlackBerry Wireless Handheld Powered by
> Gee! from
> > > > > StarHub
> > > > >
> > > > > *
> > > > > * For searches and help try:
> > > > > * http://www.stata.com/help.cgi?search
> > > > > * http://www.stata.com/support/statalist/faq
> > > > > * http://www.ats.ucla.edu/stat/stata/
> > > >
> > > > --
> > > > Justina AV Fischer, PhD
> > > > Senior Researcher
> > > > Faculty of Economics
> > > > University of Mannheim
> > > >
> > > > homepage: http://www.justinaavfischer.de/
> > > > e-mail: [email protected]
> > > > papers: http://ideas.repec.org/e/pfi55.html
> > > >
> > > >
> > > > *
> > > > * For searches and help try:
> > > > * http://www.stata.com/help.cgi?search
> > > > * http://www.stata.com/support/statalist/faq
> > > > * http://www.ats.ucla.edu/stat/stata/
> > > >
> > > > *
> > > > * For searches and help try:
> > > > * http://www.stata.com/help.cgi?search
> > > > * http://www.stata.com/support/statalist/faq
> > > > * http://www.ats.ucla.edu/stat/stata/
> > >
> > > --
> > > Justina AV Fischer, PhD
> > > Senior Researcher
> > > Faculty of Economics
> > > University of Mannheim
> > >
> > > homepage: http://www.justinaavfischer.de/
> > > e-mail: [email protected]
> > > papers: http://ideas.repec.org/e/pfi55.html
> > >
> > >
> > > *
> > > * For searches and help try:
> > > * http://www.stata.com/help.cgi?search
> > > * http://www.stata.com/support/statalist/faq
> > > * http://www.ats.ucla.edu/stat/stata/
> > >
> >
> >
> > --
> > Heriot-Watt University is a Scottish charity registered
> under charity
> > number SC000278.
> >
> >
> > *
> > * For searches and help try:
> > * http://www.stata.com/help.cgi?search
> > * http://www.stata.com/support/statalist/faq
> > * http://www.ats.ucla.edu/stat/stata/
>
> --
> Justina AV Fischer, PhD
> Senior Researcher
> Faculty of Economics
> University of Mannheim
>
> homepage: http://www.justinaavfischer.de/
> e-mail: [email protected]
> papers: http://ideas.repec.org/e/pfi55.html
>
>
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
--
Heriot-Watt University is a Scottish charity
registered under charity number SC000278.
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/