This third volume of the National Assessment of Educational Achievement series focuses on state-of-the-art procedures that need to be followed in order to ensure that the data (such as test scores and background information) produced by a large scale national assessment exercise are of high quality and address the concerns of policy makers, decision makers, and other stakeholders in the education system. Measuring student learning outcomes is necessary for monitoring a school system's success and for improving education quality. Student achievement information can be used to inform a wide variety of education policies and decisions, including the design and implementation of programs to improve teaching and learning in classrooms, the identification of lagging students so that they can get the support they need, and the provision of appropriate technical assistance and training where it is most needed. This volume in the national assessments of educational achievement series, it should become evident that the successful implementation of a national assessment exercise is a complex task that requires considerable knowledge, skill, and resources.