Study design

Diagnostic performance study requirements and dataset layout.

Requirements

  • A qualitative or quantitative variable of the measured values or indications (positive/negative) of the diagnostic test.
  • A qualitative variable indicating the true state (positive/negative) of each subject.

Dataset layout for a single test

Use a column for the true state variable (State), and a column for the test measured values (Test); each row has the values of the variables for a case (Subject).

Subject (optional) State Test
1 Diseased 121
2 Diseased 118
3 Diseased 124
4 Diseased 120
5 Diseased 116
6
7 Healthy 100
8 Healthy 115
9 Healthy 102
10 Healthy 98
11 Healthy 118

Dataset layout for paired tests

Use a column for the true state variable (State), and a column for each of the test measured values (Test 1, Test 2); each row has the values of the variables for a case (Subject).

Subject (optional) State Test 1 Test 2
1 Diseased 121 86
2 Diseased 118 90
3 Diseased 124 91
4 Diseased 120 99
5 Diseased 116 89
6
7 Healthy 100 70
8 Healthy 115 80
9 Healthy 102 79
10 Healthy 98 87
11 Healthy 118 90
 

Dataset layout for independent tests

Use a column for the true state variable (State), a column for the group (Group), and a column for the test measured values (Test); each row has the values of the variables for a case (Subject).

Subject (optional) State Group Test
1 Diseased 1 121
2 Diseased 1 118
3 Diseased 1 124
4 Diseased 1 120
5 Diseased 1 116
6 Healthy 1 100
7 Healthy 1 115
8 Healthy 1 102
9 Healthy 1 98
10 Healthy 1 118
11
12 Diseased 2 86
13 Diseased 2 90
14 Diseased 2 91
15 Diseased 2 99
16 Diseased 2 89
17 Healthy 2 70
18 Healthy 2 80
19 Healthy 2 79
20 Healthy 2 87
21 Healthy 2 90

Dataset layout for a single qualitative test

Use a column for the true state variable (State), and a column for the test indications (Test); each row has the values of the variables for a case (Subject).

Subject (optional) State Test
1 Diseased P
2 Diseased P
3 Diseased P
4 Diseased N
5 Diseased P
6 Healthy N
7 Healthy N
8 Healthy N
9 Healthy N
10 Healthy N

Frequency form dataset layout for a qualitative test

Use a column for the true state variable (State), and a column for the test indications (Test) and a column for the number of cases (Frequency); each row has the values of the variables and the frequency count.

State Test Count
Diseased Positive 3
Diseased Negative 1
Healthy Positive 0
Healthy Negative 5