One of the most important principles in both motivation and learning is working at a level that is appropriately challenging. Activities that are too easy are boring, activities that are too hard are discouraging, and either extreme leads to disengagement. The 'Background Knowledge Probe' is a classroom assessment technique (Angelo & Cross, 1993, pp. 121-125) that helps teachers determine the most appropriate level at which to begin instruction. Teachers develop short, simple, focused questionnaires that students fill out at the beginning of a course, at the start of a new unit, or prior to introducing a new topic. These probes help teachers identify the best starting point for the class as a whole. They also identify under-prepared students for whom remedial work may be needed and extremely well-prepared students who may benefit from tasks that are more challenging. The probes also help learners foreground their prior knowledge so that they can better interpret and assign meaning to new information.

Angelo, TA., and Cross, KP (1993) Classroom assessment techniques: A handbook for college teachers (2nd ed). San Francisco: Jossey-Bass.