This chapter focuses on education market systems, as one of the key issues for policy in education. Research suggests that a coherent market structure for schools is very important for attainment. The key elements are: assignment of pupils to schools and admissions policies, and school accountability and autonomy. The central element of the market structure is the assignment mechanism, which allocates each child to a school. There are different such mechanisms available: school choice, neighbourhood schooling and elite schooling or 'tracking', which assigns pupils on the basis of an exam. Other key elements include governance rules and hierarchy: school accountability and school autonomy. Finally, the nature of school leadership is tied up with the degree of autonomy -leaders are far more important in autonomous schools.