Standardized assessment in school systems has been the center of debate for decades. Although the voices of opponents of standardized tests have dominated the public forum, only a handful of scholars and practitioners have argued in defense of standardized tests. This article provides a critical synthesis of the controversial issues on state-mandated assessment of student achievement in the era of school accountability reform. By presenting an in-depth and balanced synthesis of published documents to date, this article critically reviews the 4 interlocking cornerstones of the reform's conceptual framework: assessment-driven reform, standards-based assessment, assessment-centered accountability, and high-stakes consequences. For each controversy, this article first presents the pro arguments that advocate the reform movement, followed by the con arguments that challenge the very core of the reform. The article then summarizes the debates by developing a critical synthesis of the available multidisciplinary evidence, including educational, psychometric, sociocultural, and neurocognitive research. The article concludes by proposing an action research agenda for stakeholders of different arenas and outlining future directions for standardized assessment in schools.