When attempting to identify educational settings that are most effective in improving student achievement, classroom process (that is, the way in which a teacher interacts with his or her students) is a key feature of interest. Unfortunately, high-quality assessment of the student-teacher interaction occurs all too infrequently, despite the critical role that understanding and measuring such processes can play in school improvement. This article discusses the strengths and weaknesses of two common approaches to studying these processes-direct classroom observation and annual surveys of teachers-and then describes the ways in which instructional logs can be used to overcome some of the limitations of these two approaches when gathering data on curriculum content and coverage. Classroom observations are expensive, require extensive training of raters to ensure consistency in the observations, and because of their expense generally cannot be conducted frequently enough to enable the researcher to generalize observational findings to the entire school year or illuminate the patterns of instructional change that occur across the school year. Annual surveys are less expensive but often suffer from self-report bias and the bias that occurs when teachers are asked to retrospectively report on their activities over the course of a single year. Instructional logs offer a valid, reliable, and relatively cost-effective alternative for collecting detailed information about classroom practice and can overcome some of the limitations of both observations and annual surveys.