first visit of id_no

Davidliu494 — Fri, 19 Oct 2012 17:15:30 GMT

data have;

input id_no visit measurement;

cards;

11 1 110

11 1 120

11 1 115

11 2 90

11 2 89

22 1 80

22 1 95

22 2 90

22 2 95

26 1 65

33 1 95

;

run;

for each visit, we take multiple measurement of the patient. we need to find the average of these measurements for each visit.

I run into problem trying to get the first or last visit for the same idno. so the expected output is:

11 1 115

11 2 89.5

22 1 88.3

etc...

Re: first visit of id_no

Haikuo — Fri, 19 Oct 2012 17:25:21 GMT

There will be many many ways to do it. The least mind-twisting method (may not be the fastest) is SQL:

proc sql;

select id_no, visit, avg(measurement) as avg_m from have group by id_no, visit;quit;

Haikuo