This book addresses a problem that affects the work of all educators: how traditional methods of assessment undermine the capacity of schools to serve students with diverse cultural and social backgrounds and identities. Anchored in a commonsense notion of validity, this book explains how current K-12 assessment practices are grounded in the language, experiences, and values of the dominant White culture. It presents a timely review of research on bias in classroom and large-scale assessments, as well as research on how students' level of engagement influences their performances. The author recommends practices that can improve the validity of students' assessment performances by minimizing sources of bias, using culturally responsive assessment tools, and adopting strategies likely to increase students' engagement with assessment tasks. This practical resource provides subject-specific approaches for improving the cultural and social relevance of assessment tools and offers guidance for evaluating existing assessment instruments for bias, language complexity, and accessibility issues. Book Features: Research-based recommendations for improving assessment fairness, validity, and cultural/social relevance. Practices that have been shown to improve the effectiveness of classroom assessments in supporting student learning. Concrete examples of how to create culturally relevant assessment tasks that target valued learning goals in language arts, mathematics, social studies, and science classrooms. Appendixes that provide tools educators can use to improve grading practices.