This study examined the process of curricular alignment in primary school mathematics and science. Six performance type categories were used to define the cognitive-demand levels evident in the mandated curriculum and elicited through classroom practice. The purpose of this comparative case study is to understand how the intended goals of the mandated curriculum are interpreted for planning, instruction, and assessment purposes. The data includes video-recorded lessons, interviews, planning documents, and work samples from units of work. The results revealed that interpreting the intended goals of the mandated curriculum at the classroom level is a complex and dynamic process. The process is one of iterative interpretation at various levels of curriculum planning. The alignment of performance type expectations are influenced by the "sources of authority" that are accessed, such as standardized testing programs, textbooks, and curriculum consultants. The types of performances that were privileged in assessment practices were reflected in planning and instruction at the school level, indicating that, among other factors, assessment has a critical role in determining how the curriculum is enacted.