A LONGITUDINAL STUDY WAS PERFORMED WHICH FOLLOWED THREE GROUPS OF CHILDREN (CULTURALLY DISADVANTAGED, AVERAGE, AND CULTURALLY ADVANTAGED) THROUGH GRADE THREE IN AN ATTEMPT TO DETERMINE THE RELATIVE IMPORTANCE OF THE DEVELOPMENT OF CERTAIN PERCEPTUAL FACTORS ON SUCCESS OR FAILURE IN BEGINNING READING. INSTRUMENTS USED WERE SELECTED TO IDENTIFY VISUAL, AUDITORY, AND VISUOMOTOR ABILITIES, PLUS THE EXTENT OF CONCEPT FORMATION. INSTRUMENTS USED INCLUDED THE GOODENOUGH DRAW-A-MAN SCALE, WEPMAN'S AUDITORY DISCRIMINATION TEST, METROPOLITAN READINESS TESTS, COLUMBIA MENTAL MATURITY SCALE, DURELL'S LETTER DISCRIMINATION TEST, THE WORD DISCRIMINATION TEST, THE VISUOMOTOR TEST, METROPOLITAN ACHIEVEMENT TESTS (READING), THE MAICO AUDIOMETER, AND VISUAL EFFICIENCY TEST WITH THE ORTHO-RATER. SEVEN OF THE 11 INSTRUMENTS USED WERE FOUND TO BE RELIABLE, AND THE USABILITY OF EACH WAS RECOMMENDED FOR SPECIFIC TYPES OF SUBJECTS. FOUR INSTRUMENTS NEEDED FURTHER DEVELOPMENT OR EVALUATION. (JP)