The four papers in this volume are four parts of a series on the status of recent work on measuring instruction, curriculum content, and instructional resources. These papers are intended to identify aspects of instruction, to analyze the approaches used in several leading studies, and to describe the implications of recent work for National Center for Education Statistics (NCES) data collection efforts. The first paper, "Measuring Instruction: The Status of Recent Work," by Mary S. Leighton, considers the role of instruction in "opportunity to learn" and attempts to assess instruction as part of "opportunity to learn." Implications of recent efforts to assess instruction for NCES data collection are discussed. The second paper, "Measuring Curriculum Content: The Status of Recent Work," by Mary S. Leighton and John E. Mullens considers validating national curriculum indicators and educational reform in curriculum. "Measuring Instructional Resources: The Status of Recent Work" by John E. Mullens, Lisa K. Weiner, Angela S. Williams, and Mary S. Leighton considers instructional materials and equipment, including computer-related educational technology. The final paper, "Measuring Opportunity To Learn: Advancing the State of the Art," by Mary S. Leighton, Brenda J. Turnbull, and John E. Mullens, discusses NCES studies of "opportunity to learn," focusing on elementary and secondary education, eighth-grade mathematics, fourth-grade language arts, and U.S. History. Each paper contains references. (Contains 13 tables and 2 exhibits.) (SLD)