i run the following code to transform a categorical variable.
IF (numchron =0) THEN chronic = 0;
IF (numchron =1) THEN chronic = 1;
IF (numchron =2) or (numchron =3) or (numchron =4) or (numchron =5) or (numchron =6) or (numchron =7) or (numchron = 8) THEN chronic = 2;
Then I run the following poisson regression:
proc genmod data= nb;
class chronic (ref = "0" param=ref );
class education (ref = "0" param=ref);
model ofp = education privins chronic /dist = poisson
Does chronic '1' in the estimate statement "estimate "log estimate 1 illness" chronic 1 /exp; /" actually obtain the log estimate of the chronic '1' category ? Likewise, does "estimate "log estimate 2+ illnesses" chronic 2 /exp;" obtain the log estimate for the chronic '2' category using '0' as reference?
Very confused. The results that are returned make sense, code works, just have a lingering doubt.
1) Using exp option, you're not getting the log estimate of the illness but estimate of the illness itself. You should not use the exp option if you want log estimate of the illness.
2) Your statements estimate the mean of your DV assuming that intercept=0, education=0 and privins=0. If this is what you intend to have as an output then yes it uses 0 as reference.