1 School socio-economic composition and pupil grouping in the primary school Ruth Lupton, Amelia Hempel-Jorgensen, Frances Castle, Ceri Brown 1 and Hugh Lauder 2 Introduction This paper is an early output from the ESRC-funded HARPS project 3 ; an interdisciplinary project investigating the extent to which school composition affects pupils’ experience of school and their academic outcomes, and the mechanisms by which school composition works. The particular contribution of this paper is to shed light on grouping practices in primary schools and their relationship to school composition. Much of the existing research on school composition is focused at the school level, with a smaller number of studies looking at class-level effects. We would argue that it continues to be important to investigate school-level composition effects. Influences of school mix on school resources, management and organisation, on overall approaches to curriculum, pedagogy, extra-curricular activities and learning support, and on social relations and friendship groups, are all factors that likely operate at school level, and we expect to report fully on these in the coming year as we begin to analyse the HARPs data. However, it follows that if students are systematically organised into groups for a significant part of their school day, the composition of these groups will also influence approaches to curriculum and pedagogy, the allocation of learning support resources, the nature of learning peer groups, and very possibly the formation of friendship groups outside the classroom. The more that grouping is used, the more school composition research will need to take account of the configuration and use of groups. Moreover, thinking about the potential importance of groups requires school composition researchers to engage with sociological perspectives on the interaction of pupil social class, gender and ethnicity with the processes and practices of schooling: the sociology of knowledge and the curriculum (Bernstein 1971, Whitty 1985); socio-linguistics and pedagogic practice (Bernstein 1990); the impact of policy and performative regimes in the differential valuing of pupils from different social class backgrounds (Ball 2003, Gillborn and Youdell 2000, Gewirtz 2002); and the importance of economic, cultural and social capitals in shaping pupils’ schooling experience (Bourdieu 1997, Coleman 1988) . This paper reports on the use of grouping in the twelve schools that the HARPs project has been studying in depth. Our purpose here is to use our intricate knowledge of these schools and classrooms to answer two preliminary questions: 1 All from the Institute of Education, University of London 2 University of Bath 3 Hampshire Research with Primary Schools:ESRC RES-000-23-0784