Guided reading lessons are a powerful context for beginning reading instruction, particularly for children who struggle with initial literacy learning. Providing immediate responses to students' oral reading of partially familiar texts requires teachers to make complex and highly skilled decisions. This decision process is based on knowledge of each student's previous response history and choices among strategies, cues, and possible support levels. This article provides examples to illustrate the relationship of these factors in supporting teaching decisions when listening to students' oral reading. The discussion includes a system for running record analysis to determine a student's response history. Particular attention is given to the role of self-monitoring strategies in the development of an effective processing system for beginning readers.