The Wechsler-Bellevue Intelligence Scale as A Predictor of Success In A College of Engineering

Abstract

One of t he important aspects of research apparently neglected in the Wechsler-Bellevue literature is the reliability of the scale as a predict or of academic success. There have been many studies on its reliability and validity as an intelligence test and as a clinical tool in diagnosing mental disorder. Other studies have concentrated on its reliability in a shorter form and on its relationship to similar tests. However, studies relative to its reliability as a predictive device in educational and vocational counseling are extremely limited. Purpose of This Study This study was undertaken in an effort to determine the reliability of the Wechsler-Bellevue as a predictor of success with freshmen engineering students. More specifically this investigation is directed toward accomplishing four goals; 1. The Wechsler-Bellevue subtest weighted scores, the Wechsler-Bellevue Verbal, Performance and Full Scale IQs, Form II, and five freshman engineering courses. 2. The Wechsler-Bellevue Verbal, Performance and Full Scale IQs, Form II, and the Pre-Engineering Inventory Composite Scores. 3. The Wechsler Verbal, Performance and Full Scale IQs, Form II, and the grade point average. 4. The Pre-Engineering Inventory Composite Scores and the grade point average. Rationale Intelligence tests have been used for many years as predictors of academic success. In discussing intelligence as one of the f actors affecting college grades, Daniel Harris states that “Although more and more attention has been paid to factors other than intelligence, the importance of this factor is ever with us. Various investigators report correlation with grades ranging from .33 to .64. At a number of places intelligence test scores were found to be the best single predictive device for grades.” The possibility of utilizing the Wechsler-Bellevue as an aid to educational and vocational counseling was first inferred from Wechsler's own statements. In regard to the general significance of dividing the scale into a Verbal and Performance part, he asserted that “In practice this division is substantiated by differences between posited abilities and various occupational aptitudes. Clerical workers and teachers, in general, do much better on verbal tests, whereas manual workers and mechanics do better on performance. The correlations are sufficiently high to be of value in vocational guidance, particularly with adolescents of high school age. Edward E. Anderson and collaborators in a comparative study of the Wechsler-Bellevue, Revised Stanford-Binet and the American Council on Education Tests and grade point averages state that at the college level, “…intelligence tests are expected to show some correlations with scholastic success…” However, they recognized the need for further research with the Wechsler-Bellevue in this area and suggested that “…its usefulness with college students would be limited unless its relation to grade average compared favorably with that of other tests.” It is the hope of this investigator that this study will contribute to the research on the Wechsler-Bellevue in predicting academic success. The Instruments No attempt will be made in this study to describe the Wechsler-Bellevue since it is felt that its extensive clinical use and the many studies that have been published on it are familiar to psychologists and educators alike. However, the use of Form II in this study necessitates a brief consideration of its relationship to Form I. The standardization group used by Wechsler for Form II was based on successive samples of over 1,000 cases of male adults, ages 18-40. He supplemented this sample with studies on special groups. Wechsler indicated a high correlation between the two forms with a mean difference of less than two point s between the Full Scale scores. The writer used Form II of the Wechsler-Bellevue for two reasons; namely, less work has been done with this form and 46 subjects of the total sample used in this study had already been given Form II. The Pre-Engineering Inventory is a series of tests constructed for the purpose of measuring those abilities fundamental to successful study of engineering. It is designed primarily to assist in the selection of those students who will be the most likely to succeed in an engineering school. It serves a special purpose of comparing the freshman engineering student with the other members of his class and with freshmen engineering students in general. The tests are divided into two booklets. Booklet I consists of tests measuring general verbal ability, technical verbal ability, and ability to comprehend mathematical materials. Booklet II consists of tests measuring abilities in general mathematics, mechanical principles, spatial visualization and in understanding society. The inventory is designed to be administered in two three-hour periods which may be scheduled to the same day. It can either be hand or machined scored. Eight raw scores are finally derived, one for each of the tests plus a Composite Score. These are then converted to scaled scores and to percentile ranks. The norms for the inventory are based on a selected sample of 9,994 freshmen engineering students in colleges of engineering throughout the United States. Subjects The group selected for this study consisted of 100 freshmen in the College of Engineering at the University of Detroit. Of this group, 47 were obtained from a similar study conducted by Trygg Engen, who used 50 freshmen-engineering students to compare the Wechsler-Bellevue, Form II, with academic success in the College of Engineering at the University of Detroit. Three "Subjects in his sample were excluded from the total group since they did not complete the courses required for this investigation. The entire group selected for this study was obtained by a strictly volunteer system. A freshman engineering student, for the purpose of this study, was one who had no previous college training and was enrolled in the College of Engineering at the University of Detroit from the Fall Semester of 1951 to the Spring Semester of 1953. None of the group had taken the Wechsler-Bellevue previously. Procedure The Wechsler-Bellevue, Form II, as administered to 53 freshmen engineering students during the Fall Semester of 1952. The 47 students from Trygg Engen's group were tested during the Fall Semester of 1951. Testing conditions, such as place of testing, rapport, praise and encouragement were held as constant as possible. The time of testing, however, was difficult to control and possible influences due to fatigue should be noted. The students' final grades for the first semester and their Pre-Engineering Inventory Composite Score percentiles were obtained from the office files of the Dean. The inventory is administered by the College of Engineering at the beginning of the Fall Semester as part of its regular orientation procedure. All pertinent data for each subject, i.e., name, age, date of examination, birthdate, test scores, and the final grades were transcribed to a master chart to facilitate further statistical operations. It is assured that the use of Trygg Engen's group of 47 students has little or no effect on the final data since they were investigated under similar circumstances and each examiner used the standardized procedure outlined by Wechsler for the administration and scoring of the test.