The Massachusetts Department of Elementary and Secondary Education, like other state education agencies and school districts, recognizes that the quality of instruction is a key lever to turning around low-performing schools. As part of annual monitoring of low-performing schools, the department uses Teachstone's Classroom Assessment Scoring System (CLASS) instructional observation tool to assess the quality of teacher and student interactions in three domains: emotional support, classroom organization, and instructional support. Researchers at the department and the Regional Educational Laboratory Northeast & Islands examined the relationships between schoolwide instructional observation scores gathered during annual monitoring visits to low-performing schools and schoolwide student academic achievement and growth. While relevant for policy, the associations may not be generalized to other types of schools and do not imply causal relationships. [For the full report, see ED607493; for the appendixes, see ED607495; and for the study brief, see ED607496.]