We cannot hope at present to get nearly so accurate a judgment about the frequency of deficiency in groups by means of any school test as by the psychological tests. Nevertheless, I believe that it may furnish us some supplementary evidence. The main difficulty in formulating any general rule for interpretation of the school level is that very different plans of promotion prevail in different school systems. It is not uncommon, for example, to find that a child will be promoted to a higher grade regardless of his ability provided that he has spent two years with the same teacher. This practise, of course, makes it impossible to judge a particular individual's ability by the school grade he has attained without knowing how he reached it. Nevertheless, spending two years in each grade will begin to show in a general distribution of pupils by the time we deal with 12-year-olds. I have gone over the tables of school retardation of pupils provided by Strayer for several hundred cities in the United States and I find that the percentage method of approach gives us at least a rough cue as to what might be expected by any general principle of interpretation ([189]).
Using age 7 as satisfactory in the first grade, 8 in the second, and so on, we find that among 319 cities of all sizes, half of them had 2% or more retarded four or more years in school position. This condition was about the same for cities less than 25,000 as with the larger cities. On the basis of school position for groups of children of all the school ages it would, therefore, be safer to make a low estimate of the frequency of mental deficiency on the basis of five or more years of scholastic retardation in the groups and regard 4 years or more of school retardation as a maximum estimate. Since most children leave school at 14 it is generally best to regard all older as only 14 years of age when estimating deficiency. I have not been able to check this by school and test records on a group of children through all the grades. Goddard's published records do not give the mental ages for those four or more years retarded scholastically. Moreover, he only included those in the sixth grade and below. For a group of young children this estimate would undoubtedly be too low. The delinquent groups, however, are all older. Most of them, if they lived in this country have gone to school until they were at least 14 years of age. Wallin ([211]) and Strong ([190]) also give records of school position to check the Binet rating.
TABLE XV.
Percentages of Pupils 12 and 13 Years of Age Most Seriously Retarded in School
| Percentages Retarded | ||
|---|---|---|
| 4 or more grades | 5 or more grades | |
| Cincinnati, Ohio—June 1907 | 8.8% | 2.5% |
| Cleveland, Ohio—1909-1910 | 3.0 | 0.9 |
| Des Moines, Iowa—1915 | 1.0 | 0.2 |
| Memphis, Tenn.—June 1908 | 6.6 | 1.5 |
| Minneapolis, Minn.—June 1915 | 1.3 | 0.5 |
| Pittsburgh, Pa.—1913 | 4.7 | 1.1 |
| Springfield, Mass.—Sept. 1907 | 1.2 | 0.1 |
| Reading, Pa.—1906-1909 | 2.2 | 0.4 |
The distributions for Cincinnati, Memphis and Springfield are taken from Ayres' Laggards in Our Schools. That for Minneapolis is from unpublished data. That for Reading is from Snyder's Retardation in Reading Public Schools. The others are from Superintendents' reports.
By considering only pupils in the public schools who are 12 and 13 years of age, the last years in which practically all are in school, we can get a check upon this method of estimating for delinquent groups. I have compared the age-grade distributions for those of these ages in eight cities showing the percentages retarded 4 or more and 5 or more years. They are given in Table XV. These records indicate that at least five or more years retardation below a standard of age 7 in the first grade for all who are 12 years of age or over might be taken for a low estimate of the frequency of deficiency, and four or more years retardation for a maximum estimate. Except under special circumstances those who are older than 14 years should be considered as if the highest grade attained was at 14 years of age. These borderlines of school retardation for the purpose of estimating the frequency of deficiency check fairly well with estimates for the Minneapolis and other groups of delinquents which have been tested by the Binet scale, as we shall note later in this chapter.
In order that the school test of mental deficiency should be as good as the Binet system it would have to provide a standard of school progress relative to length of attendance instead of school position relative to age. If one could say that a child was not above the lowest 0.5% of the children of his age in the progress which he had made in school relative to the time actually spent in school, one would then have an excellent standard for judging feeble-mindedness for any child who had been in school for some years. It would be better if an uncertain region were also defined. By the time that a child's ability has been passed upon for four or five years and by different teachers, even from the point of view of the needs of school work, one has a criterion for mental ability in a particular community applied under long observation, which no system of brief tests can hope to equal for some time to come. Such a standard, however, is unfortunately not available since we have too little information about school progress relative to attendance. Even if it were available, psychological tests would still be an important check upon the school judgment on account of the excessive value put upon mere memorizing in school and on account of the emotional repulsion to the school developed by some children of ability. Mental tests would be necessary, moreover, for the younger ages.
(b) School Retardation As A Warning Of The Need For Examination.
Even if no more is known than a person's grade in school at any age over eleven it is an important cue as to his mentality. Here our problem is not estimating deficiency among groups but the discovery of deficient individuals. We wish to find the highest grade in school in which we are at all likely to find children under present conditions who test in the lowest 1.5% for their ages. Our records on 653 15-year-olds indicate that a pupil of this age who tests doubtful is very rarely retarded less than 3 years in school. It occurred only twice when tested ability was judged by the 1911 tests, four times judged by the 1908 scale. None of the 15-year-olds who tested presumably deficient were retarded less than three years. In Minneapolis, as in many cities, the custom prevails of promoting, regardless of passable work, after two years have been spent in a grade.