This study is an attempt to link sociological theory and research to student grouping procedures, to administrative decision making, and to student attitudes. It is also a modest demonstration of how school administrators might more rationally assess the operation of schools as goal-directed organizations. American schools are based on an age-graded social promotion model with performance levels and curriculum groups differentiated at the secondary level. Standardized psychometric tests of achievement and ability have purportedly been used to screen students rationally for grouping assignments, and thus to promote social mobility through academic achievement. Two metropolitan area suburban high schools, one predominantly black with ability grouping, and the other with a majority of whites and heterogeneous groups within curriculum categories, were studied to determine the relative impact of different grouping procedures on their student clients. School personnel were interviewed, student records were examined longitudinally, and senior class members of each school completed self-administered questionnaires. As expected, grouping assignments within both schools were found to be highly related to social input characteristics of students and to their test scores, and vertical mobility between curriculum groups was minimal. (Authors/JM)