During 1990, the National Assessment of Educational Progress (NAEP) reported findings about elementary and secondary school students' knowledge of U.S. history, geography, and civics. In 1988, the Joint Council on Economic Education reported findings from its national study of high school students' knowledge of economics. The designers and reporters of these national assessments have assumed that their instruments measured knowledge students should have learned through involvement with the social studies curriculum in elementary and secondary school. The synthesis of findings in this digest, however, is restricted to 11th and 12th graders, students who have completed most, if not all, of the social studies curriculum. The overall achievement of these upper level high school students in the core subjects of the social studies (history, geography, civics, and economics) is dismal. Factors identified that tend to produce better performances include a home environment where reading and information are valued, limited television viewing, classroom lessons that involve utilization of knowledge and higher level performances on tests of knowledge, teacher knowledge of the subject area, and strong programs of teacher in-service education. A 9-item resource list concludes the Digest. (Author/JH)