Videos: Part 2. Using Test Information II

This multimedia segment, Part 2. Optimal Positivity Criterion - Iron Deficiency Example, includes four videos. Students are introduced to tests with continuous or categorical results, and calculate the sensitivity and specificity conditional on different ‘cutoff points’ or 'positivity criterion'. They are introduced to ROC curves and explore the implications of operating at different parts of the curve for any single test. In addition to the videos, materials include an instructor's note, companion slides, a glossary, an annotated bibliography, and sample exercises.

Access the videos.

• Video 2.1 Iron deficiency case – 1 (~10 min)
  This video demonstrates through an example of testing for iron deficiency how the sensitivity and specificity can be calculated conditional on the choice of a cutoff above which a test is called positive and below which is called negative.
• Video 2.2 Iron deficiency case – 2 (~9 min)
  In this video students continue to work through the example of iron deficiency and calculate the likelihood ratios positive and negative for a continuous test dichotomized at a certain cutoff point.
• Video 2.3 Iron deficiency case – 3 (~7 min)
  In this video students continue to work through the example of iron deficiency and calculate the likelihood ratios for a particular test categorical result.
• Video 2.4 Iron deficiency case – 4 (~10 min)
  In this video students continue to work through the example of iron deficiency and calculate the optimal positivity criterion based on the information provided.   

This multimedia segment Part 2. Optimal Positivity Criterion - Iron Deficiency (Videos 2.1, 2.2, 2.3, 2.4) was designated to follow Part 1. Introducing Continuous Test Results (Videos 1.1, 1.2, 1.3).

This teaching pack was developed by Sue J. Goldie at the Center for Health Decision Science, Harvard T.H. Chan School of Public Health. The multimedia components were developed as part of a series of pilots in the CHDS Media Hub, led by Jake Waxman, where media-based pedagogy experiments contribute to new ways of thinking about short form content.