In order to study school retardation we tabulated the school position of 236 boys and 95 girls consecutively found delinquent in the Minneapolis juvenile court. To make the results more significant we did not include any cases dismissed at their hearing in court. Comparison with more serious delinquents is made by means of the group of 100 juvenile repeaters and 123 from the Glen Lake Farm School. The school position and actual age of each delinquent was compared with the age and grade distribution among Minneapolis elementary school children. The latter was determined by a census made the same year the returns for which included about 15,000 of each sex (see Table XII).[31] The ages and grades were recorded for the beginning of September, when the school year opens, and the census was taken late in the year after all the children had been registered in school. That different groups can only be properly compared when the age-grade distributions are made for the same time in the year is clear when one remembers that the ages are changing throughout the school year while the grades remain the same for at least half the year. The census was taken for another purpose so that it unfortunately does not include the high school pupils. Since the frequency and amount of retardation increases for older ages which occur relatively more frequently in the groups of delinquents the comparison somewhat exaggerates the difference between the groups. This difference in the relative ages of the groups is allowed for, however, in a later table on which the discussion will be based. The school positions of the various groups of delinquents and of ordinary school children are given in Table XIII and graphically in Figure 2. TABLE XII. AGE AND GRADE DISTRIBUTION IN SEPTEMBER OF PUPILS IN THE ELEMENTARY SCHOOLS OF MINNEAPOLIS BOYS