As part of their improvement efforts, schools have increasingly turned to the use of data to improve instruction. This is due in part to the increasing availability of student assessment data throughout the school year. The strategy of using assessment and other data to inform teachers' instruction is often called data-driven instruction (DDI). Under DDI, teachers analyze student data to better understand students' learning needs and to identify and improve instructional practices to address those needs. This executive summary describes a larger study that examined a DDI intervention that provided substantial training and support to school leaders "and" teachers to help teachers use data effectively to improve their instruction and increase student achievement. The summary describes how the study was conducted, the DDI intervention used, key findings, and concluding thoughts. [For the full report, see ED598641.]