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st: nested models in svylogit


From   Daniel D Reidpath <reidpath@deakin.edu.au>
To   statalist@hsphsun2.harvard.edu
Subject   st: nested models in svylogit
Date   Wed, 22 Sep 2004 15:37:50 +1000

I am analyzing survey data using svylogit.

I would like to contrast two models (one nested within the other) in order to decide if Model B (the more complex model) provides a significantly better fit to the data than Model A.

Using the logistic command, it is possible to calculate the marginal reduction in the -2Log(likelihood), and it is distributed approximately as Chi-Square. This isn't provided in svylogit because of the complex design.

The logit command allows a pseudo-likelihood to be calculated with a complex survey design, but my novice reading of Aert et al (2002) "Topic in modelling clustered data" suggests that pseudo-likelihoods cannot be used in the calculation of deviance the way likelihoods could be used.

This is a long winded way of asking my question:

How does one contrast nested logistic models estimated with the svylogit command?

Daniel

*****************
Dr Daniel Reidpath Email: reidpath@deakin.edu.au
Senior Research Fellow
Social Epidemiology Tel: Local (03) 9244 6717
School of Health and Social Int. +61 3 9244 6717
Development
Deakin University Fax: Local (03) 9244 6017
221 Burwood Hwy Int. +61 3 9244 6017
Burwood VIC 3125
AUSTRALIA
Supported by a VicHealth Senior Research Fellowship
******************

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