I was running SAS on a set of 10 observations each given a rating between 1-3, and another variable A, B or C is assigned to each of them.
e.g.
Obs F1 F2
Ob1 A 1
Ob2 A 3
Ob3 B 3
Ob4 C 2
Ob5 C 3
Ob6 B 1
Ob7 A 3
Ob8 B 3
I used the following to obtain Somers'D
"Proc freq data=xxx;
tables F1*F2 / measures;
run;"
But it comes out differently from the Somers'D in the output of the logistic function
Proc logistic data=xxx;
class F1;
model F1=F2 / rsquare stb;
run;
Then I tried "model F2=F1", the Somers'D still doesn't agree with Freq.
Could anyone help me to understand this please?