In this AERA 2013 paper, Dr. Jonathan Supovitz investigates what it means for teachers to fruitfully use data to enhance the teaching and learning process. Informed by research on the challenges teachers face to use data meaningfully, and clues from the rich literature on formative assessment, this paper reports on the design and effects of an intervention designed to help teachers connect data on their teaching with data on the learning of their students for the purpose of informing subsequent instruction which leads to better student outcomes. The hypothesis of this study, therefore, is that while examining data may be useful, the real value of data use is to examine the connection between data points – in this case the instructional choices that teachers make and the learning outcomes of students. Thus, ‘data use’ in this study means encouraging and facilitating teachers’ analytical experiences of linking data on teaching to data on the learning of their students.