Figure 4

ROC curves for the diagnostic test for each configuration. The dot on each curve indicates the sensitivity and 1-specificity when the threshold for the new participant ratio is q = 1. For configuration A, when q = 1, the sensitivity is 55% and the specificity is 85%. For configuration B these values are 62% and 80%, and for configuration C they are 49% and 90%. Increasing q corresponds to moving counter-clockwise along the curve. Note that a Bernoulli random decision with probability p that a review is out of date has sensitivity p and specificity 1 - p, corresponding to an ROC curve consisting of a 45-degree line. ROC curves above the 45-degree line indicate performance superior to chance.