A new system of visual presentation of analysis of test performance: the "double-ring" diagram

Substitution of graphic representation for extensive lists of numerical statistical data is highly desirable by both editors and readers of medical journals, faced with an exploding abundance of contemporary medical literature. A novel graphic tool, the "double-ring diagram", is described herein which permits visual representation of information regarding certain statistical variables used to describe the performance of a test or physical sign in the diagnosis of a disease. The diagram is relatively easy to construct on the basis of a number of primary data such as the prevalence and the true positive, true negative, false positive and false negative test results. These values are reflected in the diagram along with the values of other statistical variables derived from them, such as the sensitivity, specificity, predictive values for positive and negative test result, and accuracy. This diagram may be useful in visualizing a test's performance and facilitating visual comparison of performance of two or more tests.