This book uses philosophical analysis to argue that there are tensions associated with using results of high stakes tests to predict students' future potential. The implications of these issues for the interpretation of test scores in general are then elucidated before their connotations for academic selection are considered. After a brief overview of the history of academic selection in the United Kingdom, and a review of evidence pertaining to its consequences, it is argued that the practice of using the results of contemporary high stakes tests to make important decisions about students incurs logical and moral problems that a conscientious educator cannot ignore. The gravity of the moral transgression depends on the purpose and significance of the test and, in the case of high stakes tests used for academic selection purposes, it is argued that, not only can the moral wrong be highly significant, but better solutions are within reach.