st: using offset with poisson and getting error message "no observations"

["valerie flaherman" <vflaherman@hotmail.com>]

Hello-- I am trying to do a poisson regression with an offset for the log of 
the population size.  Stata will do the command without an offset, but when 
I put in the offset it gives me an error message saying "no observations."  
The same happenned when I tried to use exposure. My colleagues and I are not 
sure what to do next--does anyone have advice?  Thanks so much.


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