st: poisson

[Scott Cunningham <scunning@gmail.com>]

I am estimating a Poisson with fixed effects model using:

xi:poisson depvar indepvar i.year i.id, robust

I use the "robust" to correct the standard errors because of  
overdispersion.

Moments ago, I was looking at various poisson postestimation  
commands.  I ran:

estat gof

The chi-squared result shows the poisson is not appropriate. But  
reading on, I couldn't be sure whether correcting the standard errors  
for overdispersion was the correct response to the problem the  
postestimation command was revealing.  If the chi-squared result from  
a goodness of fit result is as large as I said, but I've corrected  
the standard errors for overdispersion, then should I be skeptical of  
using Poisson in this situation?  If so, can someone help me see the  
intuition? Thanks.
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