Teachers in grades three, six, and nine in all schools in one Wisconsin county were asked to nominate children whose behavior was persistently aggressive-disruptive and children whose behavior was persistently socially approved. From 1,550 nominees, 384 were randomly drawn for study. Along with other measures, the KD Proneness Scale was administered. Data was obtained concerning (1) contact with police or sheriff departments over the 5-year period; (2) social adjustments as rated by current teachers; (3) current academic achievement in the form of Sequential Tests of Educational Progress (STEP) scores; (4) teacher grades in four curricular areas (English, Science, Math, and Social Studies); or (5) rank in graduating class for original ninth graders who were now out of school. The scale was found to be ineffective as a predictor of the youths in predicting school social adjustment and reading achievement. For example, for teacher grades, only one KD level by sex was significant: delinquency prone boys were doing less well than non-delinquency prone boys in mathematics. Tabular data and 12 references are provided. (Author abstract modified)