topic Re: Simple macro for interaction in SAS Programming

Simple macro for interaction

TJ87 — Fri, 02 Oct 2015 00:16:32 GMT

I would like to test for interactions between variable A and a set of variables (B1-B10).

In the program below, I create the interaction term (A*B) in the data step, then use the interaction term in the proc logistic step.

Could someone please suggest a macro that would help me test all ten interactions? Thank you.

data new;

set have;
int=A*B;
run;

   proc logistic data=new;
        model event= A B int;
   run;

I've tried this:

data new;
set have;

x='B1';
call symput('var',x);
int=A*&var ;
run;

   proc logisitc data=new;
        model event = &var A int;
   run;

However, I seem to get different results if I run the same program twice.

Reeza — Fri, 02 Oct 2015 03:13:39 GMT

This tutorial may be helpful:

Astounding — Fri, 02 Oct 2015 19:16:51 GMT

Assuming that LOGISTIC has no options to simplify the task, you can create the interactions without using macros:

data want;

set have;

array original {10} B1-B10;

array inters {10} inter_1 - inter_10;

do _k_=1 to 10;

inters{_k_} = A * original{_k_};

end;

run;

proc logistic data=want;

model event = A B1-B10 inter_1 - inter_10;

run;