Prior to this, my major research activity lay in the area of mathematics assessment, particularly the use of open-ended questions and the relationship between assessment and instructional practice. Three publications summarise this work: The report of the Ripple Effect Study into the connection between assessment and instruction, undertaken with Max Stephens and Mary Barnes, and published in the Journal of Curriculum Studies; The chapter on Assessment in the International Handbook on Mathematics Education; and the book Constructive Assessment in Mathematics: Practical steps for classroom teachers, published in the USA by Curriculum Press, which brought together for a teacher audience the practical implications of my work on assessment. Other research has involved the development of a theoretical structure to describe the process of (teacher) professional development. Initially this work was undertaken in 1992/93 in collaboration with Andrea Peter-Koop and then elaborated ten years later in collaboration with Hilary Hollingsworth. A complete description of the elaborated version of this model was published in the journal Teaching and Teacher Education (Clarke & Hollingsworth, 2002). Current research interests focus on multi-theoretic research designs, classroom discourse, and research synthesis.