The remedy is to be sought in differentiated courses (special classes) for both kinds of mentally exceptional children. Just as many special classes are needed for superior children as for the inferior. The social consequences of suitable educational advantages for children of superior ability would no doubt greatly exceed anything that could possibly result from the special instruction of dullards and border-line cases.[27]
Special study of the I Q’s between 70 and 79 revealed the fact that a child of this grade of intelligence never does satisfactory work in the grade where he belongs by chronological age. By the time he has attended school four or five years, such a child is usually found doing “very inferior” to “average” work in a grade from two to four years below his age.
On the other hand, the child with an I Q of 120 or above is almost never found below the grade for his chronological age, and occasionally he is one or two grades above. Wherever located, his work is always “superior” or “very superior,” and the evidence suggests strongly that it would probably remain so even if extra promotions were granted.
Correlation between I Q and the teachers’ estimates of the children’s intelligence.
By the Pearson formula the correlation found between the I Q’s and the teachers’ rankings on a scale of five was .48. This is about what others have found, and is both high enough and low enough to be significant. That it is moderately high in so far corroborates the tests. That it is not higher means that either the teachers or the tests have made a good many mistakes.
When the data were searched for evidence on this point, it was found, as we have shown in [Chapter II], that the fault was plainly on the part of the teachers. The serious mistakes were nearly all made with children who were either over age or under age for their grade, mostly the former. In estimating children’s intelligence, just as in grading their school success, the teachers often failed to take account of the age factor. For example, the child whose mental age was, say, two years below normal, and who was enrolled in a class with children about two years younger than himself, was often graded “average” in intelligence.
The tendency of teachers is to estimate a child’s intelligence according to the quality of his school work in the grade where he happens to be located. This results in overestimating the intelligence of older, retarded children, and underestimating the intelligence of the younger, advanced children. The disagreements between the tests and the teachers’ estimates are thus found, when analyzed, to confirm the validity of the test method rather than to bring it under suspicion.
The validity of the individual tests.
The validity of each test was checked up by measuring it against the scale as a whole in the manner described on p. [55]. For example, if 10-year-old children having 11-year intelligence succeed with a given test decidedly better than 10-year-old children who have 9-year intelligence, then either this test must be accepted as valid or the scale as a whole must be rejected. Since we know, however, that the scale as a whole has at least a reasonably high degree of reliability, this method becomes a sure and ready means of judging the worth of a test.
When the tests were tried out in this way it was found that some of those which have been most criticized have in reality a high correlation with intelligence. Among these are naming the days of the week, giving the value of stamps, counting thirteen pennies, giving differences between president and king, finding rhymes, giving age, distinguishing right and left, and interpretation of pictures. Others having a high reliability are the vocabulary tests, arithmetical reasoning, giving differences, copying a diamond, giving date, repeating digits in reverse order, interpretation of fables, the dissected sentence test, naming sixty words, finding omissions in pictures, and recognizing absurdities.