st: xtnbreg and alternative methods

[Mário Marques <mmarques@eeg.uminho.pt>]

Dear Statalist-Users,

I need help about xtnbreg, fe. I am using Stata 11. My dependent
variable is a count of new subsidiaries for different countries-pairs.
I have read (from Allison and Waterman, 2002) that xtnbreg, fe is not
a true fixed effects model. Dependent variable is overdispersed and
there are within individuals time-invariant covariates.

Anyway I ran xtnbreg, fe, but I would like to compare it to another model.

One of the solutions (I do not know if it is correct) is run
xtpoisson, fe and adjust standard errors upward for overdispersion
using person's chi squared or deviance. Do you think this procedure is
correct? If so, how could I get the Pearson's chi square/deviance
statistic?

Do you know about other feasible alternative methods?

Thanks for your consideration,
Mario Marques
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