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Re: st: question on GLLAMM


From   Michael Ingre <Michael.Ingre@ipm.ki.se>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: question on GLLAMM
Date   Thu, 19 Aug 2004 21:08:15 +0200

On 2004-08-19, at 16.53, Stanislav Kolenikov wrote:

If you have a
dataset of say 10000 individuals, and you also want to take some
sample design clustering into account... you are doomed to wait for a
few weeks for the model to converge.
There are however techniques to speed up -gllamm- that can be extremely efficient with large datsets, if the number of response patterns are limited. Lets say you have 10.000 observations but only 5*3*10 possible response patterns; if you use -contract , freq(_freq)- you end up with only 150 observations with varying frequency weights. This dataset should be estimated with -gllamm , weight(_freq)- in about the same amount of time as a dataset with only 150 individuals.


unless you have the latest Cray at your disposal, the model should be
kept to a moderate size. [ .... ] (It took a few days with
-oprobit- link and the panel structure with just one random effect on
my computer.)
That is so true. It just happened that two days ago I got a paper accepted for publication that summarise 323 hours (!) of computing time (Mac G4 800Mhz). A total of 10 models of varying complexity and dependent variables were estimated, 3 binary (logit) and 7 ordinal (ologit). The data was longitudinal with 60 repeated measures of 17 subjects - 1020 obs. With only two random effects I expect the models to converge in about 1/10 of the time. With 4 random effects I expect one model to converge in 200-300 hours and with 5+ random effects I probably need a Cray (or maybe a G5).

Michael

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