Teacher reports on school organizational functioning, curricular processes, and student engagement are a reliable means of ascertaining valuable information about classroom climate and learning outcomes. Yet, to date, the vast majority of quantitative teacher-reported data, where teachers themselves reach judgments about educational processes, have been summary rather than lesson specific, where teachers evaluate classroom experiences at the moment of instruction. In this study, we examine how lesson-specific teacher survey reports generate insight into the relationship between student engagement and instruction. Results suggest that this underutilized design has significant application for procuring data on within-teacher variability in practice, especially in studies focused on student engagement, active change in teacher practice, and/or teacher buy-in as a mediator of outcomes. Ultimately, we argue that lesson-specific teacher reports may be a valuable tool for researchers in measuring instructional change.