ABSTRACT
Much of our discussion in this chapter is about setting and grouping as these are the clearest manifestations of ideas of ability and symbolise this way of thinking. However, the lens of ability infl uences everyday interactions between teachers and learners and the way learners relate to each other. It is the dominant way that teachers, children, parents and policy makers think about attainment in mathematics. It is so dominant that it is often taken for granted as obviously true. Because of this it is rarely debated. We think it should be. A recent international study by the Organisation for Economic Cooperation and Development concluded that setting students should be avoided at least until upper secondary education as it is unfair and has negative effects on overall attainment (OECD, 2012 ).
