HEURISTICS FOR DETERMINING THE OPTIMAL INTERVAL BETWEEN CHECKUPS

Abstract –How often should one check on a system that is at risk for some malfunction? The optimal interval between inspections depends on the likelihood of malfunction, the cost of inspection, and the cost of treatment We develop a mathematical expression for the optimal inspection interval as a function of these parameters and then an approximation for that expression The approximation indicates that as the risk increases or the ratio of inspection to disease cost decreases by a factor of n, the inspection interval should be reduced by n1/2 We also report an experiment indicating that subjects who generate optimal inspection intervals use examples as anchors and then perform adjustments for variations in risk and cost factors However, they do not approximate the appropriate square-root adjustment rule The observed anchor-and-adjust process suggests that normative recommendations may serve as influential benchmarks, even if they are not adhered to directly.