This study was aimed at providing statistical and experiential descriptive data of value to those concerned with the type of elementary school organizational structure and facility that best serves individualized learning. Test subjects consisted of 70 boys and 62 girls enrolled in or graduated from a nongraded open plan elementary school program and facility, with a control group of 68 boys and 67 girls enrolled in or graduated from a traditional elementary school program and facility. Subjects were randomly selected from four elementary schools of the same school system and administered pre-tests at study onset and post-tests after each of the three years of the study. Factorial analysis of variance was used to analyze the independent and interactive effects that sex and type of school program had on the dependent variables of arithmetic reasoning, concepts, and computation; reading comprehension; and vocabulary. Significant effects indicated that after at least two years in the nongraded open space elementary school program, pupils had made significantly better achievement gains in most cognitive areas than had their counterparts in another type of program and facility. These effects continued during the third year. One chapter of this document contains reviews of selected studies regarding individual differences among elementary schools, vertical organization for elementary pupils and for their instruction, and national trends in elementary school organization. A statistical analysis of study results and a selected bibliography are also included. (Author/Editor)