Paul E. Newton is Professor of Educational Assessment at the Institute of Education, University of London. His research focuses primarily upon issues related to the evaluation of large-scale educational assessment systems, and he is particularly interested in theories of validity for educational and psychological measurement, past and present. He has published on a range of assessment topics, including validity, comparability, assessment purposes, national curriculum test reliability, and the public understanding of measurement inaccuracy.Having obtained a PhD in developmental psychology, Paul moved into educational assessment and has spent most of his career as a researcher within a range of assessment agencies – including the Associated Examining Board, the National Foundation for Educational Research, the Qualifications and Curriculum Authority, Ofqual and Cambridge Assessment.Paul is a member of the Editorial Board of the international journal Assessment in Education: Policy, Principles and Practice and has served on a variety of national and international committees, including the Executive Committee of the International Association for Educational Assessment. He was a member of the Assessment Reform Group, until its retirement in 2010, and is a Fellow of the Association for Educational Assessment – Europe.Stuart D. Shaw is particularly interested in demonstrating how educational, vocational and second language English assessments meet the demands of validity, reliability and fairness. Stuart has a wide range of publications in English second-language assessment and educational research journals. His assessment books include: Examining Writing: Research and practice in assessing second language writing (Shaw and Weir, 2007); The IELTS Writing Assessment Revision Project: Towards a revised rating scale (Shaw and Falvey, 2008); Validity in Educational and Psychological Assessment (Newton and Shaw, 2014); and Language Rich: Insights from multilingual schools (Shaw, Imam and Hughes, 2015). Stuart is a Fellow of the Association for Educational Assessment in Europe (AEA-E) and a Fellow of the Chartered Institute of Educational Assessors (CIEA).