Student achievement test results are the coin of the realm in educational accountability systems in the United States. For a number of years, both states and the federal government have relied heavily on tests to judge the quality of schools. The exact characteristics of the accountability systems have evolved over the years and vary a good deal from one state to another, as do the state and federal accountability systems. Despite the shared beliefs and goals, there is considerable variation in the accountability systems that have been put in place by different states. There are differences in state testing practices and differences in the stakes that are attached to results. Some of the differences in assessment and accountability systems are the result of purposeful system design decisions that are intended to meet particular goals. There are many issues that need to be addressed in the design of an educational accountability system. In this chapter, the author identifies and clarifies design issues that are critical in the creation of an accountability system that can contribute to improved teaching and student learning. Since student achievement is at the heart of the current accountability movement, a number of issues that are discussed are concerned with how student achievement is assessed. Other important issues are concerned with the uses that are made of student test results. (Contains 2 notes.)