In this chapter, the work of the MakEY team based at the University of Sheffield is outlined. The focus for this chapter is the work the team undertook on the development of an assessment tool, which was used to identify the characteristics of effective learning that could be discerned as children engaged in making. In the first section of the chapter, issues relating to assessment in makerspaces are explored, before the chapter moves on to outline an approach used in the Sheffield project to assess Characteristics of Effective Learning (COEL). COEL underpin learning and development across all disciplinary areas, and are a key element in England’s Early Years Foundation Stage (DfE, 2017). The MakEY ‘Makerspace Learning Assessment Framework’ (MLAF) is then outlined, in which children’s learning and development across a range of areas of COEL can be mapped. Finally, the chapter considers other approaches to assessment in makerspaces based on documentation and the development of narratives. First, however, an outline of the Sheffield-based project itself is provided, and the concept of ‘STEAM’ (Science, Technology, Engineering, Arts and Mathematics) is explored.