Presenting original quantitative and qualitative data from a large-scale empirical research project conducted in British secondary schools, Reassessing `Ability' Grouping analyses the impact of attainment grouping on pupil outcomes, teacher effectiveness and social equality. Alongside a comprehensive account of existing literature and the international field, this book offers: Rigorous conceptual analysis of data A view of wider political debates on pupils' social backgrounds and educational attainment A discussion of the practicalities of classroom practice Recommendations for improved practice to maximise pupil outcomes, experiences and equity Vignettes, illustrative tables and graphs, as well as quotes from teacher interviews and pupil focus groups Addressing attainment grouping as an obstacle to raising pupil attainment, this book offers a distinctive, wide-ranging appraisal of the international field, new large-scale empirical evidence, and `close to practice' attention to the practicalities and constraints of the classroom. Reassessing `Ability' Grouping is an essential read for any practitioners and policymakers, as well as students engaged in the field of education and social justice.