GWR settings: bandwidth parameter

Discussion created by research93 on Oct 1, 2012
Latest reply on Oct 15, 2012 by research93
My question is about the optimal number number of neighbours/distance to use with the GWR tool.  
I'm using GWR on a dataset with 311 area units.  When I use the adaptive kernel type and the AiCc bandwidth, the number of neighbours the program uses is 259 (out of 311 total).  There is not a lot of variation in the resulting coefficient maps.
The results are similar when I try other options (I've played with fixed kernel type and CV options).

So I tried setting the bandwidth parameter.  With 150 neighbours the residuals are not autocorrelated, and the coefficient maps show more variation. 
So now I'm wondering: should I use the AiCc/CV results, because my understanding is that ArcMap figures out the 'optimal' distance/number of neighbours? 
Or should I use the bandwidth that I set myself?  Are there some rules or guidelines that should be followed when setting my own bandwidth?
I'd really appreciate any help with this...