09-24-2014 08:39 PM
I am trying to estimate IRT a (item discrimination) and b (item difficulty) parameters from the probability of correct response (=p+ values) conditioned on each of the 8 theta points. Someone told me that I have to use logit function to get the "a" and "b" parameters. So I ran the proc Genmod procedure as shown below, but the result looks not right.
input theta p;
proc genmod data=temp;
model p=theta / link=logit, dist=poi;
Would you let me know what SAS function I have to use to get the correct "a" and "b" parameters?
09-25-2014 03:41 AM
"The result looks not right?"
How it is not right?
Why do not you use PROC IRT?
or check this paper if it may help