I believe issuing -poisgof- after the -poisson- analysis will do it.
-----Original Message-----
From: Oord, A. van den [mailto:[email protected]]
Sent: Monday, March 22, 2004 6:12 AM
To: [email protected]
Subject: st: xtpois versus xtnbreg
Hi All,
I have a data set where I count the number of patents for a group of 113
companies per year over a period of 12 years. For my analysis, I
currently use a random effects poisson model for panel data (the command
'xtpois'). However, to be certain that I am using the correct model, I
wish to determine whether my dependent variable is overdispersed or not.
In the case of overdispersion I have to use the random effects negative
binomial model for panel data (the command 'xtnbreg'). How can I
determine whether my dependent variable is overdispersed or not?
Thanks in advance,
Ad van den Oord
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