Statalist The Stata Listserver


[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

RE: st: -pcorrmat- available on ssc


From   "Nick Cox" <[email protected]>
To   <[email protected]>
Subject   RE: st: -pcorrmat- available on ssc
Date   Mon, 18 Dec 2006 15:18:57 -0000

I don't want to deny the users of -pcorrmat- any 
benefit they may derive from it, but deeply embedded here
is an elementary statistical fallacy. A variable can be (almost) 
uncorrelated with another (meaning that the correlation
is (near) zero) but nevertheless not independent of it. 
Thus a near zero correlation does not inevitably carry
no information about a relationship as it could easily
represent some nonlinear structure (e.g. curvature). 
This applies whether the correlations are partial or not. 
Thus correlations should always be considered in 
relation to graphical diagnostics. 

Nick 
[email protected] 

Raphael Fraser
 
> This is a very useful program especially in multiple regression. When
> used with pwcorr one can decide if certain variables add any
> additional information to the model by comparing the correlation and
> partial correlation coefficient.

*
*   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 1996–2024 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index