Contrast statement

[ChuksManuel]

Can anyone help me figure out how i can write a contrast statement for a 3 variable model....each model having only 2 levels (coded 0,1) in SAS. I can't find anywhere that explains this concept well. I am trying to work off this example, but it used a 2 variable model and each variable with 3 levels. Please i need help.

proc logistic data = logit_sim desc;
class x1 (ref = '1') x2 (ref = '1') / param=ref;
model y = x1 x2;
contrast 'x1 = 1 x2 1 v 2' x2 1    /e estimate = parm;
contrast 'x1 = 1 x2 1 v 3' x2 0 1  /e estimate = parm;
contrast 'x1 = 1 x2 2 v 3' x2 1 -1 /e estimate = parm;
run;

[PaigeMiller · Accepted solution]

Contrasts are generally not needed to compare one level to another. Instead, you can use the LSMEANS statement which has any number of options available to do statistical testing.

Contrasts are generally needed when you want to compare more complicated relationships than "is one level different than another level", for example, if you wanted to evaluate if 3*(mean of level 1)–2*(mean of level 2)–0.5*(mean of level 3).