In all Primary School Programme classrooms, the taught curriculum is the written curriculum in action. This aspect of curriculum includes teaching approaches required by the IB to be used. It requires that teachers plan and work collaboratively to best meet the needs of the students and that all planning of units is done using the Primary School Programme planner, a document created by the IB based on the theory of Understanding by Design. The planner, requires that teachers think about how they will assess the knowledge gained in a unit before they plan the activities of the unit.