WOLFRAM|DEMONSTRATIONS PROJECT

Analysis of Diagnostic Accuracy Measures

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plot
PPV
NPV
OR
LR+
LR-
versus
sensitivity
specificity
prevalence of disease
prevalence
0.05
healthy population
mean
0
standard deviation
1
diseased population
mean
3.67
standard deviation
1
This Demonstration shows plots of various accuracy measures for diagnostic tests on normally distributed healthy and diseased populations. This is done for differing prevalence of the disease, taking into account mean and standard deviations of the populations. The mean and standard deviations are expressed in arbitrary units. The measures considered are the positive prognostic value ("PPV"), the negative prognostic 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 plotted against the sensitivity or the specificity of the test, which can be selected by clicking the respective button.