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

Re: st: RE: GMM Estimation for Panel Data


From   Bersant Hobdari <bh.cees@cbs.dk>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: GMM Estimation for Panel Data
Date   Thu, 24 Oct 2002 08:09:26 +0200

Many thanks to both Steve Stillman and Mark Schaffer for the comments on
the use of GMM techniques for panle data.
Sincerely,
Bersant

Mark Schaffer wrote:
> 
> A quick follow-up to Steve's email.  The choice of whether to first-difference or mean-difference
> depends on whether you think the fixed/random effects are endogenous, and whether the transformed
> data are serially correlated or not.
> 
> If the effects are exogenous, then ivreg2,gmm on mean-deviation data is what you want; if the
> effects are endogenous, then you eliminate them by first-differencing and then using ivreg2,gmm.
> 
> If, after whatever transformation you've settled on, the error term of the resulting data series is
> not serially correlated, you're fine.  If it is serially correlated, then you should use ivreg2,gmm
> with the cluster(id) option, where id identifies a firm.  This will give you coefficients that are
> efficient in the presence of, and standard errors that are consistent to the presence of, arbitrary
> within-cluster correlation, which in your case means consistent to arbitrary serial correlation.
> 
> --Mark (another ivreg2 coauthor)
> 
> Quoting "Steven Stillman (LMPG)" <Steven.Stillman@lmpg.dol.govt.nz>:
> 
> > Bersant.  You can run ivreg2, gmm on data that has been first-differenced or
> > mean-differenced (for fixed effects) to correctly produce iv-gmm results for
> > panel data.  As the standard errors in these models are based on large
> > sample properties you do not need to correct the standard errors for the
> > reduction in degrees of freedom resulting from differencing the data,
> > although there is some debate out there to whether a correction should still
> > be done.  An extension to ivreg2 (I am a co-author) to handle all panel data
> > models is currently in the planning stages but I am not sure how soon it
> > will be available.
> >
> > Steve
> >
> > > -----Original Message-----
> > > From:       Bersant Hobdari [SMTP:bh.cees@cbs.dk]
> > > Sent:       Friday, October 18, 2002 7:37 PM
> > > To: statalist
> > > Subject:    st: GMM Estimation for Panel Data
> > >
> > > Hello to all List Members,
> > >
> > > I am trying to test the existence of returns to scale accross firms with
> > > different ownership structures. As the existence of simultaneity bias
> > > (due to correlation of inputs and the error term) makes OLS results
> > > inconsistent, I am using the within, first-differenced and IV-GMM
> > > to account for this problem.
> > >
> > > Here however I run into a problem. The IV-GMM procedures for Stata
> > > (ivgmm0 and ivreg2, respectively) are written not for panel data.
> > > Xtabond takes account for the panel nature of the data but it considers
> > > only dynamic models, that is not the case with the models I am
> > > esatimating. My questin is whether the former two procedures can be
> > > modified to take into account the panel nature of the data?
> > >
> > > Any suggestion would be highly appreciated.
> > > Sincerely,
> > > Bersant
> > > --
> > > Bersant Hobdari
> > > Center for East European Studies
> > > Institute of International Economics and Management
> > > Copenhagen Business School
> > > Howitzvej 60, 2000 Frederiksberg, Denmark
> > > Phone: office:  (45) 38153052
> > > Phone: mobile: (45) 26140295
> > > Fax:                (45) 3815 2500
> > > MAILTO:       bh.cees@cbs.dk
> > > *
> > > *   For searches and help try:
> > > *   http://www.stata.com/support/faqs/res/findit.html
> > > *   http://www.stata.com/support/statalist/faq
> > > *   http://www.ats.ucla.edu/stat/stata/
> >
> > The information contained in this document is intended only for the
> >  addressee and is not necessarily the views nor the official
> > communication of the Department of Labour.  All final/official papers
> > which are sent from the Department will be sent by non-electronic
> > means, on appropriate letterhead, signed by authorised personnel.
> > *
> > *   For searches and help try:
> > *   http://www.stata.com/support/faqs/res/findit.html
> > *   http://www.stata.com/support/statalist/faq
> > *   http://www.ats.ucla.edu/stat/stata/
> >
> 
> Prof. Mark Schaffer
> Director, CERT
> Department of Economics
> School of Management & Languages
> Heriot-Watt University, Edinburgh EH14 4AS
> tel +44-131-451-3494 / fax +44-131-451-3008
> email: m.e.schaffer@hw.ac.uk
> web: http://www.som.hw.ac.uk/ecomes
> ________________________________________________________________
> 
> DISCLAIMER:
> 
> This e-mail and any files transmitted with it are confidential
> and intended solely for the use of the individual or entity to
> whom it is addressed.  If you are not the intended recipient
> you are prohibited from using any of the information contained
> in this e-mail.  In such a case, please destroy all copies in
> your possession and notify the sender by reply e-mail.  Heriot
> Watt University does not accept liability or responsibility
> for changes made to this e-mail after it was sent, or for
> viruses transmitted through this e-mail.  Opinions, comments,
> conclusions and other information in this e-mail that do not
> relate to the official business of Heriot Watt University are
> not endorsed by it.
> ________________________________________________________________
> *
> *   For searches and help try:
> *   http://www.stata.com/support/faqs/res/findit.html
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/

-- 
Bersant Hobdari
Center for East European Studies
Institute of International Economics and Management
Copenhagen Business School
Howitzvej 60, 2000 Frederiksberg, Denmark
Phone: office:  (45) 38153052
Phone: mobile: (45) 26140295
Fax:                (45) 3815 2500     
MAILTO:       bh.cees@cbs.dk
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index