THE NATIONAL APTITUDE SURVEY ATTEMPTED TO PROVIDE A HIGH SCHOOL GUIDANCE INSTRUMENT TO IDENTIFY POTENTIAL AUTOMOTIVE REPAIRMEN. THE FORMAL REPORT INTRODUCES A GENERAL STATEMENT WITH THE NEEDS, THE ADVANTAGES, THE DEVELOPMENT, AND THE SAMPLE FOR THE SURVEY. THE SURVEY TEST MANUAL DISCUSSES ADMINISTRATION AND SCORING, NORMS AND PROFILES, RELIABILITY, VALIDITY, VALIDATED TEST USE, AND A SUMMARY. THE SURVEY DEVELOPED THROUGH FOUR STAGES--(1) THE TEST BATTERY'S PRESENT FORM, (2) SAMPLE PREPARATION AND ACTUAL ADMINISTRATION, (3) CLERICAL MAINTENANCE OF PARTICIPANT CONTACT THROUGH THREE FOLLOW-UPS IN SIX YEARS, AND (4) BATTERY VALIDATION AND REPORT COMPILATION. THE SIX-TEST BATTERY MEASURES FACTORS CHARACTERIZING THE OCCUPATIONAL BEHAVIOR OF EMPLOYED AUTOMOTIVE REPAIRMEN. A BIOGRAPHICAL INVENTORY INVESTIGATES SOCIO-ECONOMIC AND ATTITUDINAL FACTORS. A RANDOMLY SELECTED, NATIONALLY REPRESENTATIVE PUBLIC HIGH SCHOOL SAMPLE OF 7,265 NINTH AND 10TH GRADE BOYS WERE IDENTIFIED AND TESTED IN 1961, WITH COMPLETED INFORMATION EVENTUALLY OBTAINED FOR 80 PERCENT. THE AUTOMOTIVE AND GENERAL VOCABULARY TESTS AND THE SIX BIOGRAPHICAL INVENTORY ITEMS WERE FOUND TO BE THE BEST PREDICTORS. THE RESULTING GUIDE ESTIMATES A BOY'S CHANCES OF BECOMING A REPAIRMAN WITHIN THREE YEARS OF GRADUATION. (WR)