A commonly used index of accuracy in medical imaging trials. Equivalent to the probability of correctly classifying a random pair of cases in which one is positive and one is negative. Possible values for the area under a ROC curve range from 0.50 (random guessing) to 1.00 (perfect diagnostic performance).

See receiver-operating-characteristic curve.

a parametric curve that is generated by varying the threshold of the intrusive measure , which is a tunable parameter, and computing the probability of detection and the probability of false alarm at each operating point

a plot of true positive rate vs

In diagnostic testing, a plot of the true-positives on the Y axis versus the false-positives on the X axis; used to evaluate the properties of a diagnostic test.

"An ROC curve is a graphical representation of the trade-off between the false negative and false positive rates for every possible cut-off. By tradition, the plot shows the false positive rate on the Z axis and 1 - the false negative rate on the Y axis". (See http://www.cmh.edu/stats/ask/roc10.htm) "We are usually happy when the ROC curve climbs rapidly towards the upper left hand corner of the graph. This means that 1 - false negative rate is high and the false positive rate is low. We are less happy when the ROC curve follows a diagonal pathfrom the lower left hand corner to the upper right hand corner. This means that every improvement in false positive rate is matched by a corresponding decline in the fasle negative rate." (From the asme site).