st: suggested references about the variables to include in zero-inflated portion of zinb?

[Tim Hale <timhale@uab.edu>]

I am using zinb to estimate level of psychological distress (scores  
range from 0-24) using various demographic variables and measures of  
use of the Internet. I've used -countfit- to compare various count  
models and the results support zinb as the best fitting model.

I am uncertain, however, about how to justify the variables that I  
include in the zero-inflated part of the model. I've read journal  
articles that have used zinb, read the book by Freese and Long, and  
searched the Internet and Statalist but I have not been able to find  
any detailed recommendations or procedures. Can anyone suggest any  
other sources (books or journals) that provide an explanation or a  
good example of this process?

Ideally I would like to find a good source that I can cite in the  
paper -- but I appreciate any suggestions about this you might have.

Thanks for you help,
Tim

-----------------------------------------------------
Timothy M. Hale, MA
Graduate Assistant
University of Alabama at Birmingham
Department of Sociology
email:  timhale@uab.edu

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