Integration in Riverside Unified School District, California, justified on moral, legal, social, and educational grounds, provided a natural time-series experiment for testing the unexpected effects of lateral transmission of peer group values and normalization of instruction on the achievement of Anglos (81.5 percent), blacks (6.1 percent), and Mexican-Americans (10.7 percent). After 1-3 years integration for the various groups, results were analyzed by comparison of 1966-68 post-integration data with 1966 pre-integration cross-sectional data for primary and intermediate grades. Interpretation of these analyses supports the Coleman Report conclussion only partially: Anglo achievement was not reduced, but black and Mexican-American achievement was not improved due to integration. Determinants other than physical integration--very likely psychological and social integration--have to be considered for this continuing disparity in academic achievement. Plans and future research, based on differential input for attaining equal output, are aimed in this direction in the University of California--school district cooperative teacher education and research programs. When these plans become operative, then a test of consequence of a more sophisticated type of integration on the achievement and adjustment of Anglos, blacks, and Mexican-Americans would be available. (Author/RJ)