Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down on April 23, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: state trends


From   sara borelli <saraborelli77@yahoo.it>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: state trends
Date   Tue, 19 Oct 2010 20:46:49 +0100 (BST)

Thank you very much,
I really appreciated your help
sara

--- Mar 19/10/10, Maarten buis <maartenbuis@yahoo.co.uk> ha scritto:

> Da: Maarten buis <maartenbuis@yahoo.co.uk>
> Oggetto: Re: st: state trends
> A: statalist@hsphsun2.harvard.edu
> Data: Martedì 19 ottobre 2010, 21:39
> --- On Tue, 19/10/10, sara borelli
> wrote:
> > when using the orginal year variable I have that for
> each
> > state there is a perfect correlation between 
> > state dummy, trendstate, trandsquare_state  when
> these
> > are constructed by using the orginal year variable
> > 
> > when I look at the correlation between the same
> variables
> > constructed using the rescaled year variable then the
> > correlation is very high but not perfect.
> 
> We use the non-linearity of the relationship between a 
> variable and its square to identify the parameter for
> each.
> This is another way of saying that the correlation, which
> measures the strength of the linear relationship, must not
> be exactly 1 or -1. However, the function x2 = x^2 is
> almost
> linear in the range 1990 - 2010, which is why you get your
> 
> multicolinearity problem, but non-linear in the range 1-20,
> 
> which is why you can estimate your model in that case.
> 
> Hope this helps,
> Maarten
> 
> --------------------------
> Maarten L. Buis
> Institut fuer Soziologie
> Universitaet Tuebingen
> Wilhelmstrasse 36
> 72074 Tuebingen
> Germany
> 
> http://www.maartenbuis.nl
> --------------------------
> 
> 
>       
> 
> *
> *   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/


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