In this analysis of 58 empirical studies of high school block scheduling, the authors report findings in and across five groupings. Within groups, data were inconsistent regarding whether teachers' practices changed, but teachers believed that staff development was necessary to teach in a block schedule. Block scheduling appeared to increase student grade point averages and improve school climate, but the results regarding its effects on standardized test scores and attendance were inconsistent. Across studies, the findings indicated that (a) research studies omit key information; (b) teachers and students may view block scheduling positively (but their reasons are unknown); and (c) changes in teachers' practices are inconsistent. Many studies reported data that were collected over short periods of time. The authors of this analysis offer generalizations about block scheduling research, recommendations for further research, and a discussion of implementation issues. KEYWORDS: block scheduling, high school reform, high school scheduling patterns.As the accountability bar rises, schools continue to explore avenues for increasing student achievement, and school leaders have examined new teaching methods, emerging technologies, and alternate scheduling patterns to improve the teaching and learning processes. The National Education Commission on Time and Learning (1994) described the traditional 6-hour schedule as the "unacknowledged design flaw in American education" (p. 2). Block scheduling emerged as a way to modify the traditional 6-hour day for high school students.Although there are variations, block schedules include the 4 × 4, in which the school day is divided into four roughly equivalent blocks of time, usually 80 to 90 minutes each. Following a university model, students in a 4 × 4 schedule begin new courses twice a year. Another variation is the trimester schedule, in which the year is divided into three terms instead of two as in the 4 × 4 block schedule. In the alternating block, also called the A/B block, students meet every other day throughout the school year and typically enroll in six to eight classes, each lasting between 70 and 90 minutes.The Copernican Plan has two main configurations, each combining block periods of differing lengths during the day. In the first configuration, students enroll in one 4-hour macro-class each day (typically a core course such as algebra or English) and then in two or three shorter classes lasting between 70 and 90 minutes each. Approximately every 30 days, students receive a new schedule. In the second configuration of the Copernican Plan, students enroll in two classes lasting approximately
