The formative Assessment for Learning proposals outlined by Black and Wiliam (e.g. Black et al. , 2002 ) have been well publicised. Since 2002, in its Assessment is for Learning programme, the Scottish Executive Education Department (SEED) has been exploring ways of bringing research, policy and practice in assessment into closer alignment using research on both assessment and transformational change. This paper focuses on one project within Assessment Is for Learning, in which pilot primary and secondary schools across Scotland were encouraged to develop formative assessment approaches in classrooms. They were supported in this by researchers, curriculum developers and local and national policy-makers. The paper examines the rationale and methods behind the enactment of formative assessment in these schools. It draws upon evidence provided by the interim and final reports of participating schools to draw conclusions about areas of success within the project and potential barriers to the project's future in its evolution from pilot to national programme.