|
Match Algorithm
|
Age Caliper
|
GCP Caliper
|
Number of Pairs
|
Number Cases/Controlsb
|
Mean Distance
|
Sum of Distance
|
|---|
|
Greedy
|
1
|
1
|
8
|
7/6/1
|
1.02
|
8.15
|
|
Optimal
|
1
|
1
|
8
|
7/6/1
|
1.02
|
8.15
|
|
Greedy
|
2
|
2
|
28
|
21/14/7
|
1.90
|
53.29
|
|
Optimal
|
2
|
2
|
28
|
21/14/7
|
1.90
|
53.29
|
|
Greedy
|
3
|
3
|
38
|
26/14/12
|
2.28
|
86.54
|
|
Optimal
|
3
|
3
|
38
|
26/14/12
|
2.28
|
86.63
|
|
Greedy
|
4
|
4
|
48
|
32/16/16
|
2.87
|
137.9
|
|
Optimal
|
4
|
4
|
49
|
33/17/16
|
2.97
|
145.7
|
|
Greedy
|
5a
|
5
|
56
|
34/12/22
|
3.47
|
194.4
|
|
Optimal
|
5a
|
5
|
60
|
36/12/24
|
3.91
|
234.4
|
|
Greedy
|
6
|
6
|
62
|
37/12/25
|
3.98
|
247.1
|
|
Optimal
|
6
|
6
|
67
|
39/11/28
|
4.27
|
286.1
|
-
aCaliper is defined to be the minimum allowable difference between the case and the control. In our study, we used a caliper of five for age and GCP, and zero for the other four categorical variables
-
GCP general cognitive performance
-
bThere are three numbers listed in this column, for example 7/6/1 means seven cases were matched, six cases matched to 1:1, so six controls; and one case matched to 1:2, so two controls. This gives a total of eight matched pairs
