Hi all, I would like to first thank you all for providing your expert advise and helping us understand SAS better. I am new with these statistical modeling especially using proc genmod. My variables are Region (0-9), race (0-3), rates, cases, population and year (1996-2012). What I want to compare is rates among different racial groups across the regions (so compare 1-2, 1-3, 2-3, etc). I was told in a SAS class that proc genmod with poisson distribution would be ideal. We are dealing with not normal surveillance data and rates aren't best with other distributions. We want to control for overdispersion and get Relative Risk and Confidence intervals. We would like to see the difference over time if possible but I know it may be difficult. Does the model automatically takes the log or I should first get log and offset that. (data race; set race; Y=cases/population*100000; ln=log(Y); run; and My model goes like this proc genmod data=race; class region race; model Y=region race / dist=p link=log scale=pearson; (or 2nd model Y=region race / dist=p link=log offset=ln scale=pearson;) repeated subject=region / type=unstr; lsmeans region sex / exp cl tdiff e om; run; quit; Thanks CP
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