Test scores exert a powerful influence over people's lives. Used to determine everything from occupational fit to educational readiness to psychological health, they are tools with high-stakes consequences. If there was a time when scores could be interpreted with a one-size-fits-all-formula, the growing diversity of the American population has made that approach defunct. To help test interpreters acquire the critical thinking skills needed to read scores fairly, this book examines key psychometric ideas and judgement processes. It provides guidance on the effects of language, acculturation, poverty, disability and other areas that affect test results. Comprehensive in scope and grounded in both everyday experience and scientific rigour, this volume is a useful resource for those psychologists, government employees, educators and lawyers who are concerned about constructing equitable ways to test diverse populations.