# 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 factor (test or group indicator), 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/Group ID | Test result |
---|---|---|---|

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 binary 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 binary 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 |

## Frequency form dataset layout for 2 independent binary tests

Use a column for the true state variable (State), a column for the factor (test or group indicator), 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 | Group/Test ID | Count |
---|---|---|---|

Diseased | Positive | 1 | 3 |

Diseased | Negative | 1 | 1 |

Healthy | Positive | 1 | 0 |

Healthy | Negative | 1 | 5 |

Diseased | Positive | 2 | 24 |

Diseased | Negative | 2 | 2 |

Healthy | Positive | 2 | 2 |

Healthy | Negative | 2 | 30 |

## Frequency form dataset layout for 2 paired binary tests

Use a column for the true state variable (State), a column for each of the test indications (Test 1, Test 2) and a column for the number of cases (Frequency); each row has the values of the variables and the frequency count.

State | Test 1 | Test 2 | Count |
---|---|---|---|

Diseased | Positive | Positive | 3 |

Diseased | Negative | Positive | 1 |

Diseased | Positive | Negative | 24 |

Diseased | Negative | Negative | 2 |

Healthy | Positive | Positive | 0 |

Healthy | Negative | Positive | 5 |

Healthy | Positive | Negative | 2 |

Healthy | Negative | Negative | 30 |

- What is Analyse-it?
- What's new?
- Administrator's Guide
- User's Guide
- Statistical Reference Guide
- Distribution
- Compare groups
- Compare pairs
- Contingency tables
- Correlation and association
- Principal component analysis (PCA)
- Factor analysis (FA)
- Item reliability
- Fit model
- Method comparison
- Measurement systems analysis (MSA)
- Reference interval
- Diagnostic performance
- Measures of diagnostic accuracy
- Estimating sensitivity and specificity of a diagnostic test
- Comparing the sensitivity and specificity two diagnostic tests
- ROC plot
- Plotting a single ROC curve
- Comparing two or more ROC curves
- Area under the curve (AUC)
- Testing the area under the curve
- Difference between the areas under two curves
- Testing the difference between the areas under two curves
- Decision thresholds
- Decision plot
- Finding the optimal decision threshold
- Predicting the decision threshold
- Study design
- Control charts
- Process capability
- Pareto analysis
- Study Designs
- Bibliography

Version 5.65

Published 14-Aug-2020