Receiver Operating Characteristic (ROC) Curve

In reference to studoes of signal detection, the graphical plot of the hit rate as a function of the false-alarm rate. If these are the same, points fall on the diagonal, indiciating that the observer cannot tell the difference between the presence and absence of the signal. As the observer's sensitivity increases, the curve bows upward toward the upper left corner. That point represents a perfect ability to distinguish signal from noise