Giving students detailed feedback about the strengths and weaknesses of their work, with suggestions for improvement, is becoming common practice in higher education. However, for many students feedback seems to have little or no impact, despite the considerable time and effort put into its production. With a view to increasing its effectiveness, extensive theoretical and empirical research has been carried out into its structure, timing and other parameters. For students to be able to apply feedback, they need to understand the meaning of the feedback statements. They also need to identify, with near certainty, the particular aspects of their work that need attention. For these to occur, students must possess critical background knowledge. This article sets out the nature of that knowledge and how students can acquire it. They must appropriate for themselves three fundamental concepts - task compliance, quality, and criteria - and also develop a cache of relevant tacit knowledge.