Decoding The Data: Contingency Tables- Part 1
Scott Sherrill-Mix, Ph.D., discusses how to interpret contingency tables when evaluating diagnostic tests and associated measures of test accuracy using a real figure example.
Video Notes
Scott Sherrill-Mix, Ph.D., assistant professor in the Department of Microbiology, Genetics and Immunology at Michigan State University provides a guide on:
- How contingency tables are structured.
- How to calculate and interpret sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).
- Which calculations are population independent (sensitivity and specificity), and which are population dependent (PPV and NPV).
- Common pitfalls that lead to misleading results when applied to low鈥憄revalence populations.
Definitions mentioned during the video:
- True Positives (TP): correctly detected disease.
- False Positives (FP): healthy individuals incorrectly flagged.
- True Negatives (TN): correctly identified as healthy.
- False Negatives (FN): disease missed by the test.
- Sensitivity: proportion of actual positives correctly identified.
- Specificity: proportion of actual negatives correctly identified; measures test performance.
- Positive predictive value: proportion of predicted positives correctly identified; measures test performance.
- Negative predictive value: proportion of predicted negatives correctly identified.
Continue learning about contingency tables in part 2 of this video series. Sherrill-Mix covers how to calculate PPV when taking a test from 1 population and applying it to another population, and common pitfalls that lead to misleading results when applied to low鈥憄revalence populations.
Author Information
Scott Sherrill-Mix, Ph.D., Assistant Professor, Department of Microbiology, Genetics and Immunology, Michigan State University.
Stay up to date on all 黑料正能量Clinical Public Health Microbiology (CPHM) activities when you sign up for our monthly CPHM Newsletter. Be the first to know about free educational webinars, continuing education credit opportunities, advocacy, updated guidelines and more.
