The article discusses an interview method designed to measure delinquent behavior directly from the confidential confessions of teen-agers. The method is described and results are presented from a validation study of 125 undetected delinquents. Applica tion of the measure is illustrated with findings from a study of 522 randomly selected boys and girls, thirteen to sixteen years old, residing in Flint, Mich. Conclusions are drawn about the relationship between delinquency and social status and sex, and about the validity of official records.