In February 1989, statewide assessment tests in reading, mathematics, and writing were given to a sample of eighth graders throughout Oregon. The results and analyses of reading and mathematics assessments are presented. Important trends are described based on the analysis of data from 1985, 1987, and 1989. The 1989 information provides the first comprehensive look at student achievement in the Essential Learning Skills (ELS) strategies and basic skills that are a vital part of the new effort toward a common curriculum core in Oregon schools. Overall, Oregon eighth graders had slightly lower mathematics achievement than in 1987, with a decrease in computation scores, an increase in higher level math skills, and a more heterogeneous mixture of achievement levels. While Oregon students generally performed near the international median in the Second International Mathematics Study, they were slightly above United States levels and lower than Japanese scores. Reading test results were equivalent to 1987 scores, with gains in some areas. Significant gains were made from 1987 to 1989 in literal understanding, locating information, and implied understanding. The use of a "complete story" passage on the 1989 test was found effective. Seven figures and three tables are included. An Appendix contains one form of the reading test. (SLD)