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Re: st: Right-skewed dependent variable and spatial autocorrelation


From   Maarten Buis <maartenlbuis@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Right-skewed dependent variable and spatial autocorrelation
Date   Thu, 21 Jun 2012 15:56:53 +0200

On Thu, Jun 21, 2012 at 3:40 PM, Francisco Rowe wrote:
> 1) Normalise the dependent variable and run either a spatial autorregresive or error model. However, normalisation is problematic given the zero values in the dependent variable. Someone suggested that I could use this transformation: y*=log(y+1), so map zeros to zeros. Does it seem appropriate?

No, there are many posts on Statalist stating that that transformation
is meaningless.

> 2) Instead of using the share as dependent variable, use the count of people and run a poisson or zero-inflated poisson model with spatial autocorrelation.

A proportion is something very different from a count. 10 bachelors in
an area with 10 persons represents a completely different structure
than 10 bachelors in an area with a population of a 1000 persons. So
what model you used depends on what you want to explain.

-- Maarten

--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany


http://www.maartenbuis.nl
--------------------------

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