A dominant strand of U.S. educational policy for the past two decades has been incorporation of information about student achievement into management and regulation of schools. Although this policy idea is often attributed simply to the federal No Child Left Behind Act (NCLB), 44 states already had some form of test-based accountability (TBA) when the NCLB came into existence in 2002. NCLB transformed TBA into a national strategy, placed a clear goal on improvements in student achievement as reflected on certain standardized tests, and established a series of actions and penalties for failure to meet annual improvement goals on those tests (including school closure in the worst cases). More than 70% of the American public favors renewal of federal accountability legislation ( 1), and performance on similar tests is known to relate to important economic outcomes (2). In 2009, the U.S. Supreme Court focused on the importance of outcome accountability in a major school finance decision ( 3). Thus, TBA has become a fixture of American education. However, it is also clear that the current version could be improved significantly.