Hello Community,
When using a GLM gamma model with log link, is there a rule of thumb for when to specific the scale as the default, Pearson or deviance?
I've been reading up online, but they're always answering the question for a different distribution of GLM, and I don't think any of the answers i have found are relevant for gamma models.
Moreover, in college, I did all my statistical analysis in python, and all the packages we use had Pearson as the default scale, so that has me wondering if I've been doing it wrong the whole time!
In case it helps, here is the model setup.
ods graphics on;
proc genmod data=data;
model y = x
/dist=gamma link=log ;
run;
ods graphics off;
Thanks in advance!
Scaling with the SCALE= option is only needed as a way to attempt to deal with overdispersion as discussed in this note.
Are you ready for the spotlight? We're accepting content ideas for SAS Innovate 2025 to be held May 6-9 in Orlando, FL. The call is open until September 25. Read more here about why you should contribute and what is in it for you!
ANOVA, or Analysis Of Variance, is used to compare the averages or means of two or more populations to better understand how they differ. Watch this tutorial for more.
Find more tutorials on the SAS Users YouTube channel.