Hi @StatDave, sorry that the situation keeps shifting, but now I'm looking at cars per 1,000 people. To modify your code below would I use the following. Essentially make the new counts for each year the count per 1000 and offset by the log(population for the given year). If so, I'm now showing a modeled % change that reverses direction from the crude % change and whose confidence interval is outside the bounds of the raw number. For example, if the 89 and 111 were the per 1,000 rates (24.7% increase), the modeled rate is -10% with a 95% CI of (-31%, -3%). Am I doing something incorrectly? Thanks again for your guidance. data a;
year=1; count=Cars/1000; ln=log(Denom); output;
year=2; count=Cars/1000; ln=log(Denom); output;
run;
proc genmod;
class year;
model count=year/dist=poisson offset=ln;
lsmeans year / ilink e plots=none;
ods output coef=c;
store mod;
run;
%nlmeans(instore=mod, coef=c, link=log, f=100*(mu2-mu1)/mu1, flabel=Pct Change, title=Percent change)
... View more
