Structured observations have been conducted by researchers across the United States for several years using the Classroom Observation Measure, developed and validated by researchers at the Center for Research in Educational Policy (CREP) (Ross et al, 1991). Overall observation items from that instrument were modified to create the School Observation Measure (SOM), which represents a summary of ten 15-minute observations conducted in a single day. Multiple observations using the SOM allow researchers to determine the extent to which different common and alternative instructional practices are