The new screening instrument classifies gamblers into four gambler-types: social, regular, transitional, or problem gambler. This instrument determines independently (a) an individual's actual gambler-type by measuring his gambling activities, and (b) the individual's predicted (potential) gambler-type in terms of five variables (e.g., first gambling experience). The instrument serves a diagnostic function when a match is found between the actual and the predicted membership. This screening instrument becomes a predictive tool when an individual's actual type is more benign than his predicted type. The progress of a treatment program may be monitored if it is shown with the instrument that the predicted gambler-type becomes progressively more benign than the actual gambler-type.