From Figure 1 (which illustrates some ROC curves): > The gray line is the AROC curve for a baseline (random) classifier The AROC is the area under the ROC cur

From Figure 1 (which illustrates some ROC curves): > The gray line is the AROC curve for a baseline (random) classifier The AROC is the area under the ROC curve, not the curve itself. Also, the scale on Figure 1 for the x-axis (corresponding to the False Positive Rate, or sensitivity) go above zero and below one, which doesn't make any sense.