how to count multiple records to mark this obs as "multiple visit"

[Bal23]

proc sort data=have nodupkey;

by id date;

run;

data want;

set have;

by id date;

if first.id then index=1; else index=2;

run;

proc freq data=want;

tables cat1*cat2;

where index=1;

run;

I prevoiusly used index=2 to mark if those obs have multiple records (visits). But this has limitation, only the later visits are counted. This time I need to mark, if the patient has mulitple visit (might see doctors same day many times), whether it is the first visit, or the later visit, I want to create a variable that the patient has "multiple visit"

That means, if index=2, all the patient's records will mark as "multipe visit"

Any idea how to do? Thanks.

[Astounding · Accepted solution]

Assuming that your PROC SORT is doing the correct thing by removing multiple visits for the same patient on the same date ...

Try creating INDEX this way:

if first.id and last.id then index='Just one';

else index='Multiple';

Then adjust the WHERE statement to select whichever patients you would like.