Ordahl's study[[26]] of 61 cases who were wards of the San Jose Juvenile Court is not comparable with other groups since both sexes, both dependents and delinquents and ages from 3 to 44 were included.
Dr. Hickson ([8]) reports concerning some 2700 cases selected especially for examination from those passing through the municipal court in Chicago, in the divisions of the Boys Court, the Morals Court and the Domestic Relations Court. His tables state only average mental ages, and he classes 728 boys who average XI.11 as morons, so that I am unable to make any comparisons with his data.
Dr. Walter S. Cornell ([92]) published in 1912 the results of Binet tests on 100 cases at the Philadelphia House of Detention among whom 64% tested three or more years below normal and 41% four years or more below normal. We are unable to tell how many of these tested X or above and were thus of questionable deficiency. He also gives the results merely with the years of retardation for a group of 73 “mildly delinquent boys of Miss Wood's special school and the Children's Bureau (mostly truants).” Of this group 46% were three years or more and 25% four or more years retarded according to the tests. Again we are unable to judge how the cases were selected or what was the mental age distribution so as to discover those that fall under our borderlines, especially under the borderline of XI for the mature.
Psychological examinations have been employed in connection with the children at the Seattle Juvenile Court. Although the results are not presented in a form which can be compared with other localities, Dr. Merrill, the physician who directs the general clinic, is of the opinion that feeble-mindedness was the cause of the delinquency of only 6% of 421 consecutive cases ([148]). Previously in the same court, Dr. Smith, the psychologist, on the basis of tests, reported among 200 consecutive cases only 11 cases as feeble-minded, 5 as mentally defective, and 8 as “moral imbeciles,” a total of 13.5% ([53]).
Frau Dosai-Révész ([13]) gave a number of tests to 40 boys, 9 to 16 years of age, selected from the boys training school of the Children's Protective League in Hungary. The cases which she classified as morally feeble-minded were found to test between the normal and the feeble-minded groups.
As yet only the preliminary announcement has appeared of a study of a thousand delinquent boys and girls with the Point Scale which has been made by Bird T. Baldwin. It is to be published as a Swarthmore College Monograph (Psychol. Bull., 1917, 14, p. 78).
The reader should also consult the series of articles by L. W. Crafts and E. A. Doll appearing in the Journal of Delinquency beginning with May, 1917, on “The Proportion of Mental Defectives among Juvenile Delinquents.” It is especially valuable as a critique of the conditions desirable for exact comparison of the results of different investigations.
A Bibliography of Feeble-Mindedness in Relation to Juvenile Delinquency, compiled by L. W. Crafts, may be found in the Journal of Delinquency, Vol. I, No. 4. In Chap. II of his Problems of Subnormality, Dr. Wallin gives an admirable review of numerous studies of tested groups.
C. Summary of Tested Deficiency Among Delinquents
In bringing together these studies in which we can make somewhat comparable estimates of tested deficiency covering over 9000 delinquents, it seems possible to analyze further the question of the deficient delinquent. Comparison of the amounts of deficiency on an objective basis is scientifically a big step in advance from a reliance upon the subjective opinion of experts who cannot possibly have the same standard of deficiency in their minds. The results of the comparable investigations, on the basis of the above reinterpretation of the borderlines, are brought together in Table XI. The frequency of tested deficiency which is found among about the lowest 0.5 and 1.5% respectively of the population generally is there shown for these different groups of delinquents. This review of the studies thus assembled enables us to correct a number of impressions that have become prevalent by the early studies, as well as to formulate the general data in regard to the deficient delinquent in a manner that places the practical control of this problem on a safer foundation. We shall summarize the data under four heads.