RELATIONSHIPS BETWEEN PHYSICAL PERFORMANCE AND THE CHARACTERISTICS OF AGE, HEIGHT, AND WEIGHT OF PUPILS WERE INVESTIGATED TO FORM A BASIS FOR AN IMPROVED CLASSIFICATION INDEX TO ASSIST IN EVALUATING PHYSICAL FITNESS TEST SCORES. THE AMERICAN ASSOCIATION FOR HEALTH, PHYSICAL EDUCATION, AND RECREATION (AAHPER) YOUTH FITNESS TEST WAS ADMINISTERED TO 28,000 CHILDREN FROM GRADES 4 THROUGH 12, IN A SAMPLE OF 100 SCHOOLS. PERFORMANCE SCORES, GRADE, AGE, HEIGHT, AND WEIGHT WERE USED TO DEVELOP NORMS FOR THE TEST. A MAJOR FINDING IS THE NECESSITY FOR TAKING A PUPIL'S AGE, HEIGHT, AND WEIGHT INTO ACCOUNT IN THE INTERPRETATION OF HIS TEST PERFORMANCE. (JC)