This paper describes Detroit's "Peer Teachers as Mirrors and Monitors" project, a cost effective approach to increasing student achievement in mathematics and reading in grades one through four in Title I schools. The program consists of: (1) an observation/feedback system giving teachers data from their students' engaged-in-learning rates; and (2) four training interventions to provide teachers with management techniques, instructional strategies, research findings, and observation opportunities. Classroom observation data, attendance records and California Achievement Test results were used to evaluate the first two years of program implementation. Data indicate both project schools significantly increased the percentage of time spent in interactive instruction. The project was also successful in developing classroom observation measures, modifying teacher behavior, and implementing new instructional strategies. While the project had a positive impact, it is difficult to attribute student achievement gains entirely to this project. Observation materials, descriptive statistics, and data analysis results are appended. (BS)