teachers, parents, policy makers, and the public about student performance. The reporting of test results represents the simplest form of accountability. Stronger incentives for educational change are provided by accountability mechanisms that use information from assessments to make consequential decisions about students, teachers, or schools. Assessment and accountability policies can provide clear direction for teachers and principals in terms of student outcomes and can become a positive impetus for instructional and curricular changes (Goertz, 2000; Kelley, Odden, Milanowski, and Heneman, 2000; O’Day and Smith, 1993; Popham, 2000). When assessments are aligned with learning goals, accountability systems can motivate classroom instruction to focus on those outcomes (Stecher, Barron, Kaganoff, and Goodwin, 1998). Thus, policy makers and educators in many states view assessment linked with accountability as a powerful strategy for ensuring that all students are held to the same set of high standards (Grissmer and Flanagan, 1998; Massell et al., 1997; Olson, 2001).

Assessments can drive change at different levels of the system, for example, by informing the public about the overall state of achievement or by informing those who make decisions about teacher certification, allocation of resources, or rewards and sanctions for schools. Tests based on large, statistically selected national samples, such as the National Assessment of Educational Progress (NAEP), are designed to provide a national overview of U.S. student achievement over time (National Research Council [NRC], 1999b), often spurring state and national efforts targeted at reform. Although NAEP results provide no information about individual students, many state assessments are designed to compare individual student performance levels to specific state standards.

Assessments are designed to serve particular purposes, and assessment experts warn that a test designed for one purpose is unlikely to be appropriate for an entirely different purpose. One major issue in the late 1990s concerned the inappropriate use of