Since the great majority of children in this population were over 14.5 years of age, and since this was the assumed adult mental age used in deriving mental ages from chronological ages and I. Q. s, the M. A. s in this population are almost wholly functions of the I. Q. s.2 Self correlation obtained from population of college students retested after one semester.3 Spurious correlation has been deducted. In Musselman's formula ( 8 ) t/s = spurious r of a single test with a composite of which it is a part (t, being number of elements in a single test and s being number of elements in the composite), S was counted as 165 although it would be possible to earn 175 theoretically. Actually the maximum score in all elements except the wish element was frequently approached. Therefore, the obtained spurious r may be regarded as a little too low for all elements except the wish element, and for this it is a little too high.* Obtained from college students retested after one month. B Obtained by applying Brown's prophesy formula to a reliability of .90 ± .01 yielded by the sum of test elements exclusive of wishes. The N in the formula was counted as 1 2. However, by another population of college students the reliability of the whole OSPA score was the same (namely, .90 ± .02) as for the sum of the OSP elements alone.