THE EXTENT TO WHICH SCORES REPRESENTING PUPILS' STATUS ON CERTAIN DEVELOPMENTAL FACTORS PREDICTED THEIR ACHIEVEMENT IN READING, ARITHMETIC, AND THE MEDIAN OF A BATTERY OF ACHIEVEMENT TESTS WAS PRESENTED. THE STUDY COVERED A PERIOD OF 4 YEARS DURING WHICH THE SAME PUPILS WERE STUDIED IN THE THIRD, FOURTH, FIFTH, AND SIXTH GRADES. STUDIES OF THESE CHILDREN IN THE THIRD AND FOURTH GRADES HAD SHOWN THAT EMOTIONAL AND INTELLECTUAL ASPECTS OF DEVELOPMENT DIFFERENTIATE HIGH AND LOW ACHIEVERS. THE APPROACH IN STUDYING THE PROBLEM WAS TO OBTAIN DATA ON SEVERAL VARIABLES PURPORTING TO REPRESENT THE PHYSICAL, INTELLECTUAL, SOCIAL AND EMOTIONAL ASPECTS OF DEVELOPMENT, TO FACTOR ANALYZE THIS DATA, AND FINALLY TO COMPUTE STANDARD SCORES (MEAN EQUALS 5.0, SD EQUALS 1.0) FOR EACH VARIABLE COMPRISING EACH FACTOR. THE STANDARD SCORES WERE USED TO COMPUTE A SCORE FOR EACH DEVELOPMENTAL FACTOR, AND THE FACTOR SCORES WERE USED TO PREDICT ACHIEVEMENT. RESULTS SHOWED THE RELATIVE STABILITY OF THE FACTOR STRUCTURE OF THE DEVELOPMENTAL FACTORS. THE USE OF SCORES REPRESENTING PHYSICAL PERFORMANCE, PHYSICAL GROWTH AND EMOTIONAL DEVELOPMENT FACTORS DID NOT CONTRIBUTE SIGNIFICANTLY TO THE PREDICTION OF ACHIEVEMENT. THE INTELLECTUAL FACTOR MADE THE MAJOR CONTRIBUTION IN THE PREDICTION OF ACHIEVEMENT. THE PHYSICAL PERFORMANCE AND EMOTIONAL DEVELOPMENT FACTORS MADE THE LARGEST CONTRIBUTION OF THE NONINTELLECTUAL FACTORS, BUT THEIR CONTRIBUTION WAS RATHER SMALL. IT WAS POSSIBLE THAT THE DEVELOPMENTAL FACTORS MIGHT HAVE A MORE SIGNIFICANT CONTRIBUTION TO THE PREDICTION OF ACHIEVEMENT FOR SPECIFIC PUPILS AND FOR THE MORE EXTREME GROUPS.