The research sample was composed of 1,030 randomly selected public school children and 665 officially adjudicated delinquents from the areas of Baltimore, Indianapolis, and Phoenix, Ariz. Another group of 161 PS children from the Omaha area provided the principal data for the development of the self-report measures. The school children in the three-city sample were 12 to 16-year-old males and females. A set of 28 self-report items were used to derive the following measures: frequency of activity, diversity of activity, seriousness of activity, and progression into delinquent behavior. The measures had been used successfully in previous studies, but little attempt had been made to compare the sensitivity and interrelationships of such measures. Each item represented on kend of delinquent behavior. All measures were shown to be highly reliable and strongly intercorrelated when the data were tested for significance. The measure of frequency indicated that the students reported a mean of 0.55 occurences per item, compared with 2.16 for the delinquents. The measure of diversity, which showed how many different types of delinquent activity the children engaged in, demonstrated an average involvement in 3.49 of the categories of delinquent behavior for the school children, and in 5.59 categories for the delinquents. Cheating in school was the most common offense committed by the students, and geeting suspended from school was the most common for the delinquents. The measure of seriousness was determined by considering the frequency of delinquent acts and the seriousness of the acts as rated by the youths themselves. Significant differences were recorded between the results for both groups. A Guttman scale was utilized for the measure of progression. The scale was constructed so that any child who had engaged in a behavior positioned on the scale also had engaged in every behavior positioned at a lower point on the scale. The scale that fared the best was composed of the following itmes, form lowest to highest: drank without permission, was drunk, used marijuana, used a weapon, and stole a car. Related studies are reviewed. Data tables and graphs, footnotes, and a reference list are included.