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

Re: st: Clustering vs. Indicator variables in a Logit


From   David K Evans <dkevans@fas.harvard.edu>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Clustering vs. Indicator variables in a Logit
Date   Mon, 8 Nov 2004 11:08:00 -0500 (EST)

Including indicator variables allows for differences in the average level
of your dependent variable across groups, while clustering only allows
differences in the variance/standard errors.

Also, including indicator variables doesn't inherently imply that
observations are independent across groups (or correlated within a group).

Dave

------------------------------------------------------------------------

PhD student, Harvard Economics Department
Phone: (O) 617-495-5634, (H) 617 - 493 - 1536
Address: Currier Mail Center #554, Cambridge, MA 02138

"Why throw money at problems? That's what money is for!"
(Kurt Vonnegut, _Timequake_)

------------------------------------------------------------------------

On Mon, 8 Nov 2004 DBernstein@lecg.com wrote:

> Hello All,
>
> I understand that clustering specifies that observations be independent
> across groups while allowing for changes in variance within a group.  My
> question is how is this different than controlling for a group with  an
> indicator (0/1) variables.
>
> For example, If my data contains patient data for 12 hospitals and my LHS
> variable is (0/1) for recovery and my RHS variables include characteristic
> variables, treatment type, etc.  What is the difference between clustering
> on hospital or creating an indicator variable for each hospital?
>
> Thanks in advance for any commentary,
>
> David J. Bernstein, Ph.D.
> dbernstein@lecg.com
>
>
>
> *
> *   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/
>
*
*   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