The article discusses formative assessment, i.e. the use of evidence of current student learning in order to inform next instructional and/or learning steps. It highlights both the teacher’s and the student’s role in this endeavor. The authors discuss three aspects of current ETS research that relate to formative assessment: research projects that focus on the nature of tasks and materials to support teachers’ use of formative assessment, research projects that examine features of professional development that support teachers’ changing practices, and research projects that focus on the design of classroom observation protocols that identify and support the use of formative assessment practices. This is the 19th edition in the R&D Connections series.