This report discusses the availability and use of instructional time in relation to the requirements contained in the Hughes Hart Educational Reform and Finance Act of 1983. The study draws on information from the California Assessment Program, which supplies achievement test scores, time and coursetaking information; verbal and mathematics aptitude scores of the Scholastic Aptitude Test; California results of the High School and Beyond study; and the California Basic Educational Data System. The amount of time California students spend in school, which is currently less than the national average, is examined. The report discusses the distribution of time among subject areas in elementary school, and coursetaking and achievement in high school. National and state recommendations for improving student achievement are discussed. Methods for increasing students' academic achievement are presented. The report is a comprehensive examination of the relationship between the amount of time California students spend in school in comparison with students of other states, and the implications of the differences for learning and achievement. (DWH)