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Help interpreting estimates using log link function in GENMOD

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New Contributor
Posts: 2

Help interpreting estimates using log link function in GENMOD

 

Dear Help Community, 

 

I'm trying to understand how to interpret my estimates in the table below. I'm using GENMOD with a NEGBIN model and log link function. Are my estimates transformed, and are they log10 or natural log transformed? How can I get my response variable back to my original unit? FYI, the response is colony forming units of bacteria. 

 

 

proc genmod data=liver;

class Sex Diet;

model CFU=Sex|Diet/ Link=log Dist=NEGBIN type1 type3;

LSmeans Sex|Diet/Lines;

run;

 

 

Diet Least Squares Means

Diet

Estimate

Standard Error

z Value

Pr > |z|

A

6.8394

0.01524

448.84

<.0001

B

9.7593

0.002296

4249.98

<.0001

C

8.5384

0.02500

341.52

<.0001

D

8.4607

0.003765

2247.04

<.0001

E

14.9283

0.000149

100409

<.0001

 

Respected Advisor
Posts: 2,655

Re: Help interpreting estimates using log link function in GENMOD

The estimates are on the natural log scale. To get values on the original scale, use the ILINK option in the LSMEANS statement.

 

Steve Denham

New Contributor
Posts: 2

Re: Help interpreting estimates using log link function in GENMOD

Steve,

 

Perfecto! Thanks for the natural log confimation and ILINK trick.

 

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