Standardized testing plays an increasingly important role in the lives of today's students and educators. The U.S. No Child Left Behind Act (NCLB) requires assessment in math and literacy in grades 3-8 and 10 and, as of 2007-08, in science once in grades 3-5, 6-9, and 10-12. Based on National Center for Education Statistics enrollment projections, that will be roughly 68 million tests per year, simply to meet the requirements of NCLB. Such an intense focus on assessment, with real consequences attached for students and educators, makes it imperative that policymakers understand the complexities involved with assessment and in using assessments as part of high-stakes accountability policies. As policymakers continue to establish and revise state and national assessment and accountability systems, two overarching questions must be addressed: (1) Do current tests supply valid and reliable information?; and (2) What happens to such assessments when high stakes are attached to the outcomes? This paper offers suggestions for policymakers on how they can create policies that can support positive assessment systems. (Contains 3 resources.)