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sasgorilla
Pyrite | Level 9

Hi. I'm starting to do a poisson regression with proc genmod and wanted to first check that I have my data summarized correctly. I assumed that I could test this with the following crude model without covariates and compare the estimate with a by-hand calculation of outcome/person-time. 

proc genmod data=summarized;
	MODEL outcome=  /dist=poisson link=log offset=logdenomcount;
	estimate "Crude" intercept 1;
run;

However,  the estimate and my by-hand rate are not the same. Is my assumption these should match incorrect? 

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sasgorilla
Pyrite | Level 9

Ah, I just went back and realized I made my offset off of the _Freq_ when I did my proc summary and not the summed denominator count. Therefore my numbers were off. 

 

Correcting that now produces a match with my by-hand calculation as I thought should be the case. 

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sasgorilla
Pyrite | Level 9

Ah, I just went back and realized I made my offset off of the _Freq_ when I did my proc summary and not the summed denominator count. Therefore my numbers were off. 

 

Correcting that now produces a match with my by-hand calculation as I thought should be the case. 

Ksharp
Super User

If you want to get RATE ,check "Mean Estimate" column .

If you want to get COUNT, check "L'Beta Estimate" column.

 

Ksharp_0-1740032225825.png

 

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