[Openspace] Distance Decay Weights
koschins at uiuc.edu
Tue May 6 18:19:39 CDT 2008
on behalf of Larry.
From: Larry Plummer
Sent: Tuesday, April 08, 2008 1:29 PM
To: 'openspace at sal.uiuc.edu'
Subject: Distance Decay Weights
With apologies, I could use some help revisiting what I gather is an "old" topic. I
say old because I have found some previous comments on the openspace list
from 2005 on this topic. I'd like to know if the answer has changed since then.
How would I test the hypothesis that the friction parameter of the spatial
weights matrix equals 2 (i.e., that the spatial correlation exhibits gravity type
decay)? Is there a "definitive" reference on the subject or is this is this still an
unresolved issue? I understand that one approach is to specify the weights
matrix with varying values for the friction parameter and then accept the matrix
with the highest likelihood that also satisfies the Wald > LR > LM inequality in
the specification tests. However, I also note from Dr. Anselin's "Under the
Hood" paper that, "when both the original values (xk) and the spatial lag (Wxk)
for the same variable are included [in a regression], tests for the importance of
distance decay can be performed (distance decay implies gk < bk)." These two
approaches seem to get me only part way to a solution to my problem.
Second, in gauging the goodness-of-fit, how critical is it that the W > LR > LM
Larry Plummer, PhD
Assistant Professor of Management
(Strategy and Entrepreneurship)
Department of Management
101 Sirrine Hall
Clemson, SC 29634
lplumme at clemson.edu
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