Policymakers continue to view student assessment as an appealing instrument of education policy, and they have found a wider variety of uses for it over the past two decades. This article explores the policy uses of assessment, focusing particularly on its persuasive role in encouraging higher levels of educational performance and on its accountability and regulatory functions. The purpose is to provide a framework that will help explain the reasoning of policymakers who continue to insist that assessments can be used for multiple purposes, even in light of their own prior experience and expert evidence to the contrary.