st: html format postings to Statalist

["Schaffer, Mark E" <M.E.Schaffer@hw.ac.uk>]

Marta,
 
I have a question for you - how did you manage to send an email to
Statalist in html format?  According to the FAQ,
 
http://www.stata.com/support/faqs/res/statalist.html#advice
 
it shouldn't have gone through.
 
I tried posting this to the list in html format as well, and it failed
to get through, which is what I expected - but it makes your success
even more puzzling.
 
--Mark


________________________________

	From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of
M.Sanchez-Sache@lse.ac.uk
	Sent: Thursday, August 23, 2007 2:45 PM
	To: statalist@hsphsun2.harvard.edu
	Subject: RE: RE: RE: ivreg2 
	
	
	Mark,
	 
	It's much clearer now. Thanks again.
	 
	Marta.

________________________________

	From: owner-statalist@hsphsun2.harvard.edu on behalf of
Schaffer, Mark E
	Sent: Wed 22/08/2007 23:15
	To: statalist@hsphsun2.harvard.edu
	Subject: st: RE: RE: ivreg2 
	
	

	Marta,
	
	> From: owner-statalist@hsphsun2.harvard.edu
	> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of
M.Sanchez-
	> Sache@lse.ac.uk
	> Sent: 22 August 2007 18:51
	> To: statalist@hsphsun2.harvard.edu
	> Subject: RE: RE: ivreg2
	>
	> Mark,
	>
	> Thanks for your answer. However, something stills puzzles me.
Why
	would we
	>  interested in uncentered statistics if we do have a constant
in our
	model?
	> When STATA computes uncentered statistics, is it not taking
into
	account the
	> constant we explicitly introduce in our model? I thought that
	uncentered
	> statistics were only used when a constant was lacking in the
model.
	>
	> Thanks again.
	>
	> Marta
	
	I can think of two reasons.  First, sometimes users might
estimate a
	model with the -nocons- option but the model actually does have
a
	constant.  (For example, if the regression is on individuals and
there
	is a gender dummy, the user might exclude a constant and include
both a
	male and a female dummy.)  From a programming point of view, it
was
	easiest just to report both centered and uncentered R-sqs and
let the
	user decide which s/he wants to use.  Second, we don't always
use
	regressions to estimate models; sometimes we do tests based on
	artificial regressions.  There are N*R-sq tests which require
the
	uncentered R-squared.
	
	Cheers,
	Mark
	
	> -----Original Message-----
	> From: owner-statalist@hsphsun2.harvard.edu
	> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of
	> Schaffer, Mark E
	> Sent: 22 August 2007 18:35
	> To: statalist@hsphsun2.harvard.edu
	> Subject: st: RE: ivreg2
	>
	> Marta,
	>
	> > -----Original Message-----
	> > From: owner-statalist@hsphsun2.harvard.edu
	> > [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of
	> > M.Sanchez-Sache@lse.ac.uk
	> > Sent: 22 August 2007 18:09
	> > To: statalist@hsphsun2.harvard.edu
	> > Subject: st: ivreg2
	> >
	> > I'm using ivreg2 command. It doesn't report an ANOVA table
and,
	> > instead, it reports uncentered and centered TSS and
r-squared. Why
	> > does it report uncentered TSS and r-squared if I'm including
a
	> > constant in my regression and, therefore, centered TSS and
r-squared
	
	> > are valid? Why does it report both?
	> >
	> > Thanks a lot in advance.
	> >
	> > Marta.
	>
	> It reports both because sometimes people want the centered
	> R-sq and sometimes they want the uncentered R-sq.  Seemed the
	> easiest way to program it and still give users statistics
	> they might find useful.
	>
	> Cheers,
	> Mark (co-author of ivreg2 along with Kit Baum and Steve
Stillman)
	>
	> Prof. Mark Schaffer
	> Director, CERT
	> Department of Economics
	> School of Management & Languages
	> Heriot-Watt University, Edinburgh EH14 4AS tel
	> +44-131-451-3494 / fax +44-131-451-3296
	> email: m.e.schaffer@hw.ac.uk
	> web: http://www.sml.hw.ac.uk/ecomes
	>
	>
	> >
	> > Please access the attached hyperlink for an important
electronic
	> > communications disclaimer:
	> >
http://www.lse.ac.uk/collections/secretariat/legal/disclaimer.htm
	> >
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