Also known as the Relative Operating Characteristics, it is a graphical plot of the sensitivity, or true positive rate (true deceivers correctly identified), vs. false positive rate (percent of non-deceivers falsely implicated), for a given separation of the distribution of all possible scores for all possible choices of threshold. It is a psychophysical conceptual model for detection efficiency based on signal detection theory (SDT). The ROC characterizes the sensitivity of the decision criteria versus the specificity, and is useful to predict false positive and false negative rates across all levels of a criterion (cutting score, in PDD). It is an extension of work from the 1940s regarding the ability of radar operators to discriminate radar signals of friendly aircraft from those of enemy aircraft or noise. See: Swets (1995); Swets, Dawes & Monahan (2000).