APA Dictionary of Psychology

in a detection, discrimination, or recognition task, the relationship between the proportion of correct yes responses (hit rate) and the proportion of incorrect yes responses (false-alarm rate). This is plotted on a graph to show an individual’s sensitivity on the particular task: The axes are hit and false-alarm rates, points are marked to denote the different rates obtained under different conditions, and the points are connected to form a smooth arc. For example, a ROC curve may be used to indicate how well a person detects a specific tone in the presence of noise. A single quantitative index of performance may be calculated from the curve as well. Also called isosensitivity function; response-operating characteristic curve. See also d prime.