peter_m

local multicollinearity / local collinearity - local VIF test in ArcGIS for GWR

Discussion created by peter_m on Jan 13, 2013
Hallo froum members,

I´m trying do slove a hedonic GWR model for house prices but I have some extrem coefients :-( !

As I have found out I had to do something with the collinearity of the variables and that there are several "types" of collinearity. So you can group them in:

- global collinearity and
- local collinearity

1. Question:
Is collinearity and multicollinearity the same/wahts the difference?
(Because in both context global/local they are used and I have found no easy explanation in words)

2. Question:
I have checked:
+ global collinearity with
[INDENT]- global "multi"collinearity (tested with VIF (variance inflation factor) and ok - all values < 3,5)[/INDENT]
+ local collinearity with
[INDENT]- local "multi"collinearity (tested with variation of variables in ArcGIS GWR - all condition number < 30)[/INDENT]
But I still have tow variables in the model with very extrem coefients which indicates collinearity as I think!

So I have do to another collinearity or mulitcollinearity check?

I have found these ESRI resources but I don´t get further with that! (It seems I have done all but I have the bad feeling that I have still some collinearity because of some realy estrem coefients !!!)
http://resources.arcgis.com/en/help/main/10.1/index.html#//005p00000031000000
http://forums.arcgis.com/threads/14233-GWR-Help-Error-040038

Thanks for your help!

Peter

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