Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: st: Using Levprdict to predict values of second dataset
From
Maarten Buis <[email protected]>
To
[email protected]
Subject
Re: st: Using Levprdict to predict values of second dataset
Date
Wed, 14 Mar 2012 16:03:48 +0100
On Wed, Mar 14, 2012 at 3:54 PM, NEPPC RA wrote:
> I am using a regression to estimate log(per capita expenditure) in a
> certain subset of my data, let's call it subset "A". I then want to
> use the results from that regression to estimate values for a
> completely different subset. Usually I can simply regress on the
> variables in question and then specify predict X. However, since it is
> logged I am using levpredict to reduce transformation bias. I noticed
> that levpredict is only creating estimates for the observations used
> in the regression. Thus, it is skipping the second subset for which I
> am trying to estimate costs. Any suggestions?
The answer is not to model log(expenditure) but to model expenditure
with the log link function. You can either do this with -glm- or
-poisson-, see:
Nicholas J. Cox, Jeff Warburton, Alona Armstrong, Victoria J. Holliday
(2007) "Fitting concentration and load rating curves with generalized
linear models" Earth Surface Processes and Landforms, 33(1):25--39.
<http://dx.doi.org/10.1002/esp.1523>
and:
<http://blog.stata.com/2011/08/22/use-poisson-rather-than-regress-tell-a-friend/>
--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany
http://www.maartenbuis.nl
--------------------------
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/