10-28-2016 10:43 AM
I want to know if there is a way that I can elimnate refrence option in class statement using genmod procedure?
Because when I run my model, it gives me the last category of each variable in the class as a reference to that variable.
10-28-2016 11:05 AM
A classification variable compares the effect of each level to SOMETHING. Often the comparison is to a reference level, but it could also be to last level, the first level, or the average effect over all levels.
The documentation for "Parameterization of Model Effects" discusses the various ways to choose a parameterization for a CLASS variable. For interpretation and applications of different parameterizations, see Pasta (2005).
For PROC GENMOD, you can use the PARAM= option to choose the parameterization. For example:
CLASS C / param=effect ref='MyRefLevel';