How to structure the input data for PROC MDC?

Linh1 — Mon, 29 Apr 2019 02:09:12 GMT

I'm preparing my data to run proc MDC but kept receiving the error: "ERROR: The NCHOICE= option is not allowed when the number of choices for each individual (ID) is not the same." I don't really get what it means. Could you help me figure out what's wrong?

The original dataset (final1) is a panel transaction data that has the columns: customerid, week, brand, p1 p2 p3 p4 d1 d2 d3 d4 f1 f2 f3 f4.

(P1-P4 are average price of brand 1-4 in that week, respectively. D1-4 are dummy variables showing whether that brand is displayed in store, f1-4 are dummy variables that show whether brand 1-4 are featured in the store ads)

I used this code to prepare the data and the outcome is in the attached file:

data mergemnl(keep=pid decision mode c1 c2 c3 p d f);
set final1;
array pvec{4} p1 p2 p3 p4;
array dvec{4} d1 d2 d3 d4;
array fvec{4} f1 f2 f3 f4;
array s1{4}(1 0 0 0);
array s2{4}(0 1 0 0);
array s3{4}(0 0 1 0);

retain pid 0;
pid + 1;
do i = 1 to 4;
mode = i;
p = pvec{i};
d = dvec{i};
f = fvec{i};
c1 = s1{i};
c2 = s2{i};
c3 = s3{i};
decision = ( brandnum = i );
output;
end;
run;

This is the code I used to run mdc:

proc mdc data=mergemnl;
model decision =c1 c2 c3 p d f /
type=clogit
nchoice = 4
optmethod=qn
covest=hess;
id pid;
run;

Re: How to structure the input data for PROC MDC?

ChrisNZ — Mon, 29 Apr 2019 02:10:35 GMT

Message was moved to procedure thread and title shortened.

topic How to structure the input data for PROC MDC? in SAS Procedures

How to structure the input data for PROC MDC?

Re: How to structure the input data for PROC MDC?