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mbcox
Calcite | Level 5

I am running a poisson regression model for the number of admissions for a group of patients (identified by "ID").  The explanatory variables are post (pre vs post period) and case (case vs control) with an interaction term post*case.  As each patient can have more than one admission, I have added a repeated subject statement to the model.  However, after adding the repeated subject statement to the code the output for the model no longer gives the deviance.  How can I specify that the output for the model include the deviance?

proc genmod data=alldata;

class ID;

model admit = post case post*case / dist=poisson link=log offset=logtime;

repeated subject=ID;

run;

Any suggestions would be appreciated!

2 REPLIES 2
lvm
Rhodochrosite | Level 12 lvm
Rhodochrosite | Level 12

When you add a repated statement, you are perform GEE, which involves a quasi-likeliood (not a true likelihood or true distribution). Thus, the deviance (which is based on a true likelihood) is not printed.

mbcox
Calcite | Level 5

Thank you for your reply.  Do you know how I can run this type of model with the repeated subject statement and force SAS to output the deviance?  Or do you have a suggestion of another model that would be better for this situation?  Thank you.

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