I. Introduction The need for rapid auditory screening tests to measure the hearing of large numbers of persons is more urgent today than at any time in the history of the field of audition. The interest in conservation of hearing of school children and of military and industrial personnel has aroused an unprecedented interest in the measurement of hearing. This interest has stimulated research workers to attempt new, quick ways of identifying persons who may have a significant hearing loss. There are two basically different methods currently used to measure hearing; one gives a record of the auditory threshold, and the other screens at fixed intensity levels and gives only pass or fail results. Either of these methods, as currently applied, is too time-consuming to satisfy the requirements of rapid testing of large groups. To see why this is so, let us consider the two methods more fully. Measurements of