The results of a critical survey of research on educational effectiveness, performed to assess the current state of knowledge regarding the determinants of educational outcomes, are reported. An input-output approach was used to analyze the relationship between the amounts of various resources provided to students and the educational outcomes. Other approaches used were the process approach, the organizational approach, the evaluation approach, and the experimental approach. It was found that school resources are not consistently important, and that the role of peer-group influences is complex. Major implications of the research include the following: (1) Research has not identified a variant of the existing system that is consistently related to students' educational outcomes; (2) Increasing expenditures on traditional educational practices is not likely to improve educational outcomes substantially; and (3) There seem to be opportunities for significant reduction of redirection of educational expenditures without deterioration in educational outcomes. (For related document, see ED 058 473.) (Author/CK)