The constancy of the I.Q.

Abstract

That the constancy of the intelligence quotient has attracted much attention is shown by the great amount of research that has been done in order to verify the theory of constancy. Much of the literature concerning the problem has been concisely summarized by Foran (36, 37), Burks ( 16), and Baldwin (60). They have considered many of the studies in which the Stanford Revision of the Binet-Simon Tests was used; therefore, there seems to be a need for a review of investigations dealing with the constancy of the I.Q. derived from revisions of the Binet-Simon Tests other than the Stanford-Binet and group tests. Furthermore, various researches on the influence of training, environment, and physical condition on. the I.Q. have been made.

"Constancy" of the IQ.

“…Both raw correlations and correlations corrected for estimated test unreliability were presented. These were: The results of these studies fit in quite well with the general trend of earlier investigations, and the size of the correlations reported here is comparable to the average for the Stanford-Binet and for group tests reported in Nemzek's summary (75).…”

“…In the thirties, however, relatively few such studies have appeared. Studies of too recent a date to be included in Nemzek's review (75) are reported below.…”

The child's intelligence.

“…The critical point then seems to be how constant is the I.Q. Numerous studies may be consulted on this point (9,34,35,47,48,50). As regards I.Q., the average deviation from one examination to a subsequent examination is reported by these various studies to be about five points in either direction.…”