Dear All,
I am trying to fit a model for count data using Negative binomial regression, it gives incident rate ratios for the variables in the model, one of the options for this type of model is specifying the offset variable while fitting the model in stata using glm. This offset should be the person years (if i am correct). however I do not have data on this variable. My question is:
Is it correct to fit the model without an offset and would the Incident rate ratio be still correct to report If I do not specify the offset variable in the model?
I will really appreciate any help.
Thank you,
M Riaz
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