Most other nations have a very different approach to measuring academic achievement at the end of high school and signaling that information to universities and other interested parties. In Australia, Denmark, England, Scotland, Finland, France, Ireland, the Netherlands, and many Canadian and German provinces, for example, high school exit examinations are developed by (or under the supervision of) the same Ministry of Education that establishes content standards for each subject, funds K-12 education, and regulates the training and licensing of teachers. This article reviews empirical evidence on the effects of three different approaches to assessing and signaling achievement to students, parents, colleges, employers, and the local community. It begins by describing the critical features of these approaches to signaling and accountability and how they contrast with the system of student stakes built around aptitude tests and teacher grades that prevailed during the 1960s and 1970s. The second section explains the theory of action behind the expectation that these new signaling/accountability systems will raise teacher standards and student effort and achievement above the levels that prevail when diplomas are based on seat time and high-stakes college admission decisions are based largely on teacher grades and three-hour-long multiple-choice format aptitude tests. The third section of the article reviews the empirical literature on the effects of voluntary and universal curriculum-based external exit examinations and minimum competency examinations on learning, school attendance, and labor market outcomes. The final section analyzes the impact of changes in state policies regarding signaling and accountability on gains in eighth-grade National Assessment of Educational Progress (NAEP) mathematics achievement since 1990. (Contains 1 figure, 1 table and 9 notes.)