For the past seven years, Missouri has been administering the Missouri Mastery and Achievement Tests (MMAT) to fulfill the requirements of the Excellence in Education Act of 1985. The MMAT, as a criterion-referenced test, can measure student progress on specific key skills over time. This summary presents results of the spring 1993 administration of the MMAT for grades 3, 6, 8, and 10. Data for grades 3 and 6 are based on the total population (about 50,000 for each grade), and data for grades 8 and 10 are based on about 10% of test takers. Trend data from 1991 and 1992 are also presented. Scaled scores from 1993 show a general upward trend in student performance. Scores decreased from 1991 to 1993 only for grade-6 social studies, grade-10 English/language arts, and grade-10 social studies. Key skills mastered by the typical (median) student have also increased slightly or remained stable since 1991. The MMAT continues to provide the framework for fulfilling the goals of excellence in education. Three figures and one table present study data. (SLD)