This digest reviews testing and score reporting requirements contained in the No Child Left Behind Act of 2001 (NCLB) and examines factors that could delay or dilute the Act's guarantee of educational accountability for the academic achievement of all children. It outlines how states will implement federally-mandated testing requirements, highlighting students with limited English proficiency, those with disabilities, and those who come from economically disadvantaged backgrounds. It discusses what kinds of tests should be used and when they must be administered; who must be tested and who is exempted; whose scores count and how they should be reported; and how the NCLB's testing and adequate yearly progress requirements are established and implemented by the states. The digest concludes that a variety of stakeholders must be included in the regulatory and enforcement processes of NCLB, and that the Department of Education must expand and strengthen the quality of data collected for accountability purposes.(SM)