STATISTICAL DATA WAS COMPILED FROM A DETAILED STUDY IN ONE ELEMENTARY SCHOOL SYSTEM OF CLASS COMPOSITIONS, DISTRIBUTIONS OF ABILITIES, AND ACHIEVEMENT BY RACES. PROCEDURES USED IN CARRYING OUT THE STUDY AND MAKING THE ANALYSES ARE OUTLINED. ALL OF THE STATISTICAL DATA IS SUMMARIZED IN A SERIES OF TABLES. BASED ON THIS DATA, SEVERAL CONCLUSIONS CAN BE DRAWN. FIRST, NEGRO AND WHITE CHILDREN ARE ALMOST UNIFORMLY DISTRIBUTED THROUGHOUT EACH CLASS AND GRADE. SECONDLY, THE MEAN INTELLIGENCE SCORE OF NEGRO CHILDREN IS 12.9 POINTS BELOW THAT OF WHITE CHILDREN, ALTHOUGH THE DIFFERENCE IS LESS IN SECOND AND THIRD GRADES. THE RANGE OF INTELLIGENCE MEAN SCORES SUGGESTS THAT THERE IS A CONSISTENCY OF GROUPING PRACTICES. FINALLY, THE ACHIEVEMENT LEVELS OF BOTH NEGRO AND WHITE CHILDREN APPEARS TO BE RISING. THE DIFFERENCE IN MEAN ACHIEVEMENT LEVELS CONTINUES TO FAVOR WHITE CHILDREN, BUT IF INITIAL SOCIOECONOMIC FACTORS ARE COMPENSATED FOR, LEVELS MAY BE EXPECTED TO BECOME EQUAL.