Background: Professional standards for validity of achievement tests have long reflected a consensus that validity is the degree to which evidence and theory support interpretations of test scores entailed by the intended uses of tests. Yet there are convincing lines of evidence that the standards are not adequately followed in practice, that…

Education policy in the U.S. in the last two decades has emphasized large-scale assessment of students, with growing consequences for schools, teachers, and students. Given the high stakes of such tests, it is important to understand the relationships between students' answers to test items and their knowledge and skills in the tested content…