Threshold Setting and the Cycling of a Decision Threshold

摘要

When policy makers use a test result with a cutoff score in a decision, the cutoffthreshold may change over time. An example is the threshold of "reasonable suspicion"used to justify a police search. Hammond (1996) postulated that a decision threshold willoscillate over time in response to competing pressures from affected constituencies, asunavoidable cases of false positives (e.g. innocent people searched) and false negatives(e.g. guilty people overlooked) emerge from the uncertainty of using an imperfect test(e.g. level of evidence) to predict the actual measure of interest (e.g. guilt). Thestructural underpinnings of a cycling threshold are analyzed in this theory-buildingarticle. First, we present a simplified converging model of Hammond's initial insight.Then, we present three alternative models: one with integral control representing thehistorical dissatisfaction of competing constituencies; a second model with delays inpolicy maker responsiveness; and a third with stakeholders’ shifting constituencies.