topic Re: SET_ID IN CASE CONTROL MATCHING in SAS Programming

SET_ID IN CASE CONTROL MATCHING

momolito — Fri, 31 Mar 2023 06:47:22 GMT

I am a new SAS user. I have been trying to match cancer cases to controls in a ratio of 1:5. I have sucessfully matched them in one data set that looks like this,

study_id control_id num
11 13 1
11 111 2
11 112 3
11 113 4
11 13 5
14 15 1
14 16 2
14 19 3
14 20 4
14 115 5
29 30 1
29 31 2
29 32 3
29 129 4
2 131 5

However, I would like to combine the study_id and control_id in one column, and also generate a new variable called set_id that appears as in the table below (this will be used as the strata in subsequent analysis). How do i transform my data to have the variables ID and SET_ID as in the table below? Thanks

ID SET_ID CANCER
11 1 1
13 1 0
111 1 0
112 1 0
113 1 0
14 2 1
15 2 0
16 2 0
19 2 0
20 2 0
115 2 0
29 3 1
30 3 0
31 3 0
32 3 0
129 3 0
131 3 0

Re: SET_ID IN CASE CONTROL MATCHING

andreas_lds — Fri, 31 Mar 2023 11:25:12 GMT

If the dataset is sorted by study_id, try this:

data want;
   set have;
   by study_id;
   
   if first.study_id then do;
      set_id + 1;
      id = study_id;
      cancer = 1;
   end;
   else do;
      id = control_id;
      cancer = 0;
   end;
   
   drop study_id control_id num;
run;

Re: SET_ID IN CASE CONTROL MATCHING

Ksharp — Fri, 31 Mar 2023 11:48:03 GMT

data have;
input study_id control_id num;
cards;
11      13                 1
11      111                2
11      112                3
11      113               4
11      13                 5
14      15                 1
14      16                 2
14      19                 3
14       20                4
14      115               5
29       30                1
29       31                2
29      32                 3
29     129                4
29      131                 5
;

data want;
 set have;
 by study_id;
 set_id+first.study_id;
 if first.study_id then do;
   id=study_id;cancer=1;output;
 end;
 id=control_id;cancer=0;output;
keep id set_id cancer;
run;

Re: SET_ID IN CASE CONTROL MATCHING

momolito — Thu, 04 May 2023 12:00:37 GMT

Thank you so much, this works too