Many states and school districts are making concerted efforts to boost student achievement in mathematics and science. These are not simple face lifts, but attempts to develop deep, lasting changes in how students learn these critical subjects. This Brief is intended for those who seek to improve student learning by creating coherent systems of expectations and assessments in states and districts. Other potential audiences are those who study reform, make decisions about reform, and are affected by reform. The intention of this Brief is to help people think more clearly about the concept of alignment, and to help them examine what is required for expectations and assessments to be in alignment.