The fifth edition of Educational Measurement represents the first version of this volume produced solely by the National Council on Educational Measurement (NCME). This volume, like the previous four editions, provides cutting edge research and guidance on all major topics in the field of measurement science, with chapters written by acknowledged experts in their respective fields. Edited by Linda L. Cook and Mary J. Pitoniak, this edition contains 22 chapters separated into four parts. Part I provides a framing chapter for the volume, as well as chapters on the history and the social context of educational measurement. Part II addresses the important topics of validity, reliability, and fairness theory and concepts. Part III includes new theories and technical advances in topics such as technology-based assessment; scaling, equating and linking; test administration and scoring; standard setting; modeling educational assessment data; score reporting; fairness and accessibility; and designing and developing assessments. Part IV includes chapters on assessment to inform instruction and learning; test-based accountability in K-12 testing; testing in higher education; licensing and certification assessment; testing of interpersonal and intrapersonal skills; and large-scale assessment in international contexts. Part V provides an extensive discussion on the nature of measurement.This is an open access title available under the terms of a CC BY-NC-ND 4.0 license. It is free to read at Oxford Scholarship Online and offered as a free PDF download from OUP and selected open access locations.