The pedagogical potential of classroom assessment to support student learning has increasingly been evidenced in research over the past decade. Constructive classroom assessment has been championed by assessment specialists, and endorsed by professional organizations. In practice, however, the process of changing classroom assessment from its traditionally summative orientation is not straightforward. This methodical review looks at how six sources, which are educational research, evaluative inquiry, large-scale assessment, educational policy, professional development, and teachers' beliefs, influence and mediate assessment practices. A group of purposively selected research articles are analysed as evidence of the dynamics in this complex process. Cross-currents relating to research perspective, collaboration, and time are discussed. For the movement seen in this study to continue, the tension between teacher autonomy and school community, and the relationship between collective commitment and assessment literacy should be considered. (Contains 1 table and 1 figure.)