## Technical Report VII

#### Wolfram Demonstrations Project

# Uncertainty of Measurement and Diagnostic Accuracy Measures

### A T Hatjimihail

#### Abstract

This Demonstration compares various diagnostic accuracy measures of two diagnostic tests. The two tests measure the same measurand, for normally distributed nondiseased and diseased populations, for various values of the prevalence of the disease, of the mean and standard deviation of the populations, and of the uncertainty of measurement of the tests. A normal distribution of the uncertainty is assumed. The mean and the standard deviation of each population and the uncertainty of each test are measured in arbitrary units. The measures compared are the positive predictive value (PPV), the negative predictive value (NPV), the (diagnostic) odds ratio (OR), the likelihood ratio for a positive result (LR+), and the likelihood ratio for a negative result (LR-). The measures are calculated versus the sensitivity or the specificity of each test. That can be selected by pressing the respective button. The types of plot are: both measures (first test: blue plot, second test: orange plot), partial derivatives of both measures with respect to uncertainty (first test: blue plot, second test: orange plot), difference, and ratio of the two measures. The types of plot can be selected by pressing the respective buttons, while the seven parameters can vary using the sliders.

#### Published

2018

#### Citation

Hatjimihail AT. Uncertainty of Measurement and Diagnostic Accuracy Measures. Technical Report VII. Drama: Hellenic Complex Systems Laboratory, 2018. https://www.hcsl.com/TR/hcsltr07/hcsltr07.pdf