In the Minneapolis group of elementary school children it will be found that there is about as much chance of a child being in either of the two most common ages for a grade. Among the boys, for example, 36% were in the series represented by age 6 in the first grade, 7 in the second grade, 8 in the third grade, etc., while 30% were in the series represented by one year older for each grade. It is, therefore, reasonable to regard either 6 or 7 as a satisfactory age in the first grade, 7 or 8 in the second, when one estimates the amount of retardation in this group. The allowance of two ages as satisfactory for a grade is in conformity with the practise of Strayer ([189]). The necessity of taking these ages at either the beginning or the end of the school year, and not merely “in the grade,” is emphasized by the report of the New York City Committee on School Inquiry ([72]). Ayres ([71]) also considers only those pupils over-age who are over 7 in the first grade, 8 in the second, etc., so that this may be regarded as fairly well established as a standard for measuring the retardation in school position of groups of children.
The summary of results in Table XIII shows that 70% of the ordinary delinquent boys were retarded in school position as compared with 27% among the Minneapolis boys in the elementary schools, 91% of the ordinary delinquent girls as compared with 23% of the Minneapolis girls of these schools. When one compares the age distribution of the delinquent groups, given in Table XIII with that of the Minneapolis school children in Table XII, it is clear that an allowance should be made for the much larger proportion of older children in the delinquent groups. This may be done by determining the percentage retarded at each age and in each group and then calculating indices of retardation by weighting the percentage retarded at each age in the proportion to the number of delinquents at that age. Table XIV gives these results for the ages 8 to 15 inclusive.
For example, in calculating the indices 39 and 70 for the frequency of retardation among ordinary delinquent boys as compared with elementary school boys, the percentages retarded at each life-age for each of these groups was multiplied by the number of ordinary delinquent boys at this age, as shown lower in the table, and the totals divided by the number of ordinary delinquents, 213. The average frequency of the retardation of a school group which compares in ages with the delinquent group was thus determined. In calculating the indices of amount of retardation the same procedure is followed except that the average number of years retarded is found for each age and this is multiplied by the number of delinquents at that age. The 16-year-olds are omitted because of the inadequacy of the school census for this age. According to the standard which regards 7 years as satisfactory in the first grade there can be no retardation under eight years of age. Since some of the pupils 13 years of age and over have reached high school and so do not show in the Minneapolis table the percentage of retardation for children 13-15 years is based on the assumption that the number of children at these ages will be the same as the average number for 11 and 12 years. No credit could be allowed for those advanced in school positions on account of the incompleteness of the Minneapolis census for older ages. The comparison is, therefore, on the basis of retardation alone.
TABLE XIV.
Indices of Frequency and Amount of School Retardation of Minneapolis Juvenile Delinquents Compared with Minneapolis School Children of Corresponding Ages.
(Age 7 or younger regarded as satisfactory in the first grade.)
| RETARDATION | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Percentage Retarded at Each Life-Age | |||||||||
| Index | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | |
| School Boys | 39% | 8 | 16 | 24 | 31 | 35 | 40 | 45 | 43 |
| Delinquent Boys | 70% | 0 | 44 | 50 | 67 | 58 | 60 | 77 | 93 |
| School Boys | 36% | ||||||||
| Glen Lake Boys | 86% | 17 | 50 | 46 | 66 | 81 | 61 | 87 | |
| School Girls | 35% | 7 | 12 | 16 | 25 | 31 | 33 | 37 | 93 |
| Delinquent Girls | 90% | 0 | 100 | 50 | 50 | 75 | 83 | 95 | 100 |
| Index | Average Amount of Retardation in Years | ||||||||
| School Boys | .61 Yr. | .09 | .19 | .31 | .43 | .54 | .63 | .78 | .64 |
| Delinquent Boys | 1.27 Yr. | .00 | .66 | .50 | .86 | 1.09 | 1.11 | 1.23 | 2.11 |
| School Boys | .54 Yr. | ||||||||
| Glen Lake Boys | 1.54 Yr. | .17 | .50 | .62 | 1.25 | 1.86 | 2.11 | 2.03 | |
| School Girls | .64 Yr. | .07 | .15 | .22 | .34 | .45 | .50 | .59 | .82 |
| Delinquent Girls | 2.29 Yr. | .00 | 1.00 | 1.00 | 1.00 | 1.25 | 2.25 | 2.05 | 2.84 |
| Totals | Number of Children at Each Life-Age | ||||||||
| School Boys | 13,123 | 1650 | 1624 | 1614 | 1552 | 1742 | 1647 | 1647 | 1647 |
| Delinquent Boys | 213 | 3 | 9 | 6 | 21 | 25 | 47 | 56 | 46 |
| Glen Lake Boys | 108 | 0 | 6 | 8 | 13 | 12 | 21 | 18 | 30 |
| School Girls | 12,781 | 1634 | 1617 | 1594 | 1623 | 1552 | 1587 | 1587 | 1587 |
| Delinquent Girls | 82 | 2 | 1 | 2 | 2 | 4 | 12 | 21 | 338 |
Index equals the sum of retardation at each age multiplied by the number of delinquents at that age divided by the total number of delinquents.
From the indices of frequency of retardation in Table XIV it will be seen that retardation of one or more years below the standard of age 7 in the first grade is nearly twice as common among the ordinary delinquent boys as among a group of school boys of corresponding ages, while it is fully 2½ times as great among the ordinary girl delinquents as among a corresponding group of school girls, when estimated on the same basis.
To understand the significance of this comparison one should consider the relative difference which is shown between school children and delinquents in the statistics of health, defective sight, nose and throat obstructions, etc. The percentages of consecutive delinquents showing other defective or diseased conditions has never, so far as the writer is aware, been found to be double that among the school children generally when figured on a corresponding basis. Medical inspection shows that for other conditions than retardation the frequency of defects and disease found among representative groups of ordinary juvenile delinquents can often be equaled in the poorer schools of the city. To find a factor relatively twice as common among delinquents as among school children, when the frequencies are as great as with retardation, means a variation that is unquestionably significant. This is, of course, not an argument against the detection and treatment of handicaps that can be benefited by the physician. It only suggests the relative size of the two problems.