Re: st: Count data with known upper limit

["Santos Silva, J.M.C." <jmcss@essex.ac.uk>]

Hi there,

You may want to consider the beta-binomial distribution; I have used it 
in a paper dealing with count data with known upper limit . Additionally, 
you many want to look at the Stata code I have here:  
http://privatewww.essex.ac.uk/~jmcss/flex.zip
An example illustrating the use of the command is available here: 
http://privatewww.essex.ac.uk/~jmcss/flex_example.zip

All the best,

Joao


> Dear Statalisters,
> I am trying to analyze count data where the outcome is the sum of 5 
> dichotomous variables -each of these 5 variables is associated with a 
> specific ?Fail/Pass? criterion. Given this upper limit (of 5), such data 
> don´t seem to be ?very Poisson-like?.
> Alternatively, I have also thought of an ordered logit model with 5 ordered 
> categories (that is, one category for each possible count). However, I am not 
> sure that those categories would have much sense given the sum structure of 
> those outcome data (that is, a given sum outcome may result from various 
> combinations). To possibly solve this issue, I have heard that the 
> homogeneity of those 5 constructed categories may be checked but I am unsure 
> about the way to do such a check.
> Any suggestion or references to select the appropriate model (and Stata 
> commands) for those count data with a known upper limit would be very helpful.
> Many thanks.
> Sébastien
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