| Procedure features: |
|
| Tables: |
MATCH_11, MATCH
|
This example uses a table that contains data for a case-control study.
Each row contains information for a case or a control. To perform statistical
analysis, you need a table with one row for each case-control pair. PROC SQL
joins the table with itself in order to match the cases with their appropriate
controls. After the rows are matched, differencing can be performed on the
appropriate columns.
The input table MATCH_11 contains one row for each case and one row
for each control. Pair contains a number that associates the case with its
control. Low is 0 for the controls and 1 for the cases. The remaining columns
contain information about the cases and controls.
data match_11;
input Pair Low Age Lwt Race Smoke Ptd Ht UI @@;
select(race);
when (1) do;
race1=0;
race2=0;
end;
when (2) do;
race1=1;
race2=0;
end;
when (3) do;
race1=0;
race2=1;
end;
end;
datalines;
1 0 14 135 1 0 0 0 0 1 1 14 101 3 1 1 0 0
2 0 15 98 2 0 0 0 0 2 1 15 115 3 0 0 0 1
3 0 16 95 3 0 0 0 0 3 1 16 130 3 0 0 0 0
4 0 17 103 3 0 0 0 0 4 1 17 130 3 1 1 0 1
5 0 17 122 1 1 0 0 0 5 1 17 110 1 1 0 0 0
6 0 17 113 2 0 0 0 0 6 1 17 120 1 1 0 0 0
7 0 17 113 2 0 0 0 0 7 1 17 120 2 0 0 0 0
8 0 17 119 3 0 0 0 0 8 1 17 142 2 0 0 1 0
9 0 18 100 1 1 0 0 0 9 1 18 148 3 0 0 0 0
10 0 18 90 1 1 0 0 1 10 1 18 110 2 1 1 0 0
11 0 19 150 3 0 0 0 0 11 1 19 91 1 1 1 0 1
12 0 19 115 3 0 0 0 0 12 1 19 102 1 0 0 0 0
13 0 19 235 1 1 0 1 0 13 1 19 112 1 1 0 0 1
14 0 20 120 3 0 0 0 1 14 1 20 150 1 1 0 0 0
15 0 20 103 3 0 0 0 0 15 1 20 125 3 0 0 0 1
16 0 20 169 3 0 1 0 1 16 1 20 120 2 1 0 0 0
17 0 20 141 1 0 1 0 1 17 1 20 80 3 1 0 0 1
18 0 20 121 2 1 0 0 0 18 1 20 109 3 0 0 0 0
19 0 20 127 3 0 0 0 0 19 1 20 121 1 1 1 0 1
20 0 20 120 3 0 0 0 0 20 1 20 122 2 1 0 0 0
21 0 20 158 1 0 0 0 0 21 1 20 105 3 0 0 0 0
22 0 21 108 1 1 0 0 1 22 1 21 165 1 1 0 1 0
23 0 21 124 3 0 0 0 0 23 1 21 200 2 0 0 0 0
24 0 21 185 2 1 0 0 0 24 1 21 103 3 0 0 0 0
25 0 21 160 1 0 0 0 0 25 1 21 100 3 0 1 0 0
26 0 21 115 1 0 0 0 0 26 1 21 130 1 1 0 1 0
27 0 22 95 3 0 0 1 0 27 1 22 130 1 1 0 0 0
28 0 22 158 2 0 1 0 0 28 1 22 130 1 1 1 0 1
29 0 23 130 2 0 0 0 0 29 1 23 97 3 0 0 0 1
30 0 23 128 3 0 0 0 0 30 1 23 187 2 1 0 0 0
31 0 23 119 3 0 0 0 0 31 1 23 120 3 0 0 0 0
32 0 23 115 3 1 0 0 0 32 1 23 110 1 1 1 0 0
33 0 23 190 1 0 0 0 0 33 1 23 94 3 1 0 0 0
34 0 24 90 1 1 1 0 0 34 1 24 128 2 0 1 0 0
35 0 24 115 1 0 0 0 0 35 1 24 132 3 0 0 1 0
36 0 24 110 3 0 0 0 0 36 1 24 155 1 1 1 0 0
37 0 24 115 3 0 0 0 0 37 1 24 138 1 0 0 0 0
38 0 24 110 3 0 1 0 0 38 1 24 105 2 1 0 0 0
39 0 25 118 1 1 0 0 0 39 1 25 105 3 0 1 1 0
40 0 25 120 3 0 0 0 1 40 1 25 85 3 0 0 0 1
41 0 25 155 1 0 0 0 0 41 1 25 115 3 0 0 0 0
42 0 25 125 2 0 0 0 0 42 1 25 92 1 1 0 0 0
43 0 25 140 1 0 0 0 0 43 1 25 89 3 0 1 0 0
44 0 25 241 2 0 0 1 0 44 1 25 105 3 0 1 0 0
45 0 26 113 1 1 0 0 0 45 1 26 117 1 1 1 0 0
46 0 26 168 2 1 0 0 0 46 1 26 96 3 0 0 0 0
47 0 26 133 3 1 1 0 0 47 1 26 154 3 0 1 1 0
48 0 26 160 3 0 0 0 0 48 1 26 190 1 1 0 0 0
49 0 27 124 1 1 0 0 0 49 1 27 130 2 0 0 0 1
50 0 28 120 3 0 0 0 0 50 1 28 120 3 1 1 0 1
51 0 28 130 3 0 0 0 0 51 1 28 95 1 1 0 0 0
52 0 29 135 1 0 0 0 0 52 1 29 130 1 0 0 0 1
53 0 30 95 1 1 0 0 0 53 1 30 142 1 1 1 0 0
54 0 31 215 1 1 0 0 0 54 1 31 102 1 1 1 0 0
55 0 32 121 3 0 0 0 0 55 1 32 105 1 1 0 0 0
56 0 34 170 1 0 1 0 0 56 1 34 187 2 1 0 1 0
;
MATCH_11 Table 1
First 10 Rows Only
Pair Low Age Lwt Race Smoke Ptd Ht UI race1 race2
------------------------------------------------------------------------------------------------------------
1 0 14 135 1 0 0 0 0 0 0
1 1 14 101 3 1 1 0 0 0 1
2 0 15 98 2 0 0 0 0 1 0
2 1 15 115 3 0 0 0 1 0 1
3 0 16 95 3 0 0 0 0 0 1
3 1 16 130 3 0 0 0 0 0 1
4 0 17 103 3 0 0 0 0 0 1
4 1 17 130 3 1 1 0 1 0 1
5 0 17 122 1 1 0 0 0 0 0
5 1 17 110 1 1 0 0 0 0 0
 |
options nodate pageno=1 linesize=80 pagesize=60; |
| |
proc sql;
create table match as
select
one.Low,
one.Pair,
(one.lwt - two.lwt) as Lwt_d,
(one.smoke - two.smoke) as Smoke_d,
(one.ptd - two.ptd) as Ptd_d,
(one.ht - two.ht) as Ht_d,
(one.ui - two.ui) as UI_d |
| |
from match_11 one, match_11 two
where (one.pair=two.pair and one.low>two.low); |
| |
title 'Differences for Cases and Controls'; |
| |
select *
from match(obs=5); |
Differences for Cases and Controls 1
Low Pair Lwt_d Smoke_d Ptd_d Ht_d UI_d
--------------------------------------------------------------------
1 1 -34 1 1 0 0
1 2 17 0 0 0 1
1 3 35 0 0 0 0
1 4 27 1 1 0 1
1 5 -12 0 0 0 0
Copyright © 2010 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
