Validities of the four aptitude indexes of the Armed Services Vocational Aptitude Battery (ASVAB), Form 1, and the Airman Qualifying Examination-66 (AQE), were determined for final grades in 46 airman training courses. Comparisons were made between AQE and ASVAB in terms of their ability to predict technical school success. The data demonstrate the ASVAB is an effective instrument for use in the military high school testing program and may be used satisfactorily, as is AQE, to assign enlistees to technical training. Three of the four selector aptitude indexes of the ASVAB (General, Administrative, and Electronics) evidenced their appropriateness by having higher validities for their appropriate courses than any of the other ASVAB aptitude indexes. This sort of specific validity did not obtain for the selector index of the Mechanical cluster. However, 15 of the 16 validities obtained for the selector index in the Mechanical area were at a significant (.01), useful and acceptable level. (Author)