The Validity of the Detroit Alpha Intelligence Test in Grades IV to VIII as Correlated with the Wechsler Intelligence Scale for Children

Abstract

Purpose of the Study This study was made for the purpose of investigating the validity of the Detroit Alpha Intelligence Test, Form S, for grades IV to VIII by correlating it with the Wechsler Intelligence Scale for Children. The validity of the Detroit Alpha was determined by use of the correlations obtained by a Pearson Product Moments technique. Value of the Study Borrowing from Lindquist we know that “The validity of a test may be defined as the accuracy with which it measures that which it is intended to measure, or as the degree to which it approaches infallibility in measuring what it purports to measure" In this study the validity of the Detroit Alpha is measured by correlating it with the well known and well-standardized Wechsler Intelligence Scale for Children. Thus, if fairly good correlation with the WISC can be found on the various scales of t he Detroit Alpha, or even one scale and for different grades, one can see the advantage of using the group test to appraise a large number of pupils within the school setting. There is no need to mention the impracticability of attempting to test every pupil individually. The Detroit Alpha Intelligence Test is used extensively within the Detroit School System to evaluate pupil intelligence and predict future school performance. In an interview with Dr. Harry Baker, who devised the test, he mentioned to the author that very little attempt has been made to standardize the Detroit Alpha with a nationally standardized test; other than a correlation study made with the Short Form of the California Test of Mental Maturity using Form S with 98 subjects. On this study a correlation of .834 ± 02 was obtained. Dr. Baker feels that the Detroit Alpha is adequate for predictability purposes within Detroit's own schools, but he admits of its shortcoming in not being adequately validated against reliable nationally standardized tests and feels such a study is justifiable area for research. Since the Detroit Alpha Intelligence Test is being used extensively in the Detroit School System as a group test of intelligence it is of value to know how well it measures intelligence by comparing it with a good reliable tool. Procedure The validity of the Detroit Alpha Intelligence Test, Form S, grades IV to VIII was determined by its Pearson Product -Moment correlation with the WISC. 1. The Detroit Alpha raw scores of the Language Scale for each separate grade were correlated with the WISC Verbal Scale scaled scores for each separate grade. This yielded a Pearson correlation of WISC Verbal Scale to Detroit Alpha Language Scale for each grade. In addition, the overall correlation of all grades for the WISC Verbal Scale and the Detroit Alpha Language Scale was found. 2. The correlation between the WISC Performance Scale and the Detroit Non-Language Scale was found for each grade and then the overall Performance or Non-Language correlation as in 1 above. 3. The correlation between the WISC Full Scale and the Detroit Full Scale was found for e ach grade and then for the overall Full Scale correlation as in 1 and 2 above. 4. The levels of significance were found for e ach correlation obtained as in 1, 2 and 3 above. 5. The me an scores were found for each grade on the language, non-language and full scales for both the WISC and the Detroit Alpha. Next, the means of these means for language, non-language and full scales and for all grades were found. 6. The standard deviations from each mean and mean of the means for 4 above were found . No attempt was made to cross-correlate the various scales, i.e. WISC Verbal to Detroit Performance, WISC Performance to Detroit Verbal, WISC Verbal to Detroit Full, etc., as typical of the 3x3 method of comparison. Such a comparison study is broader in scope than this paper and might prove to be a valuable study.