Susan Janssen Creighton is a senior mathematics associate at Education Development Center (EDC) in Massachusetts. She has worked in mathematics education for 30 years, both in schools and at EDC, where her work has focused largely on K–12 mathematics curriculum development and mathematics teacher professional development. Currently, her work focuses on helping mathematics teachers adopt and successfully implement formative assessment practices, and on supporting teachers’ understanding and use of the CCSS Standards for Mathematical Practice. As a member of the NSF-funded project, Formative Assessment in Mathematics Classrooms: Engaging Teachers and Students (FACETS), she was a lead facilitator for several of the participating districts. She is a co-author of Bringing Math Students Into the Formative Assessment Equation.