In 2005, to address concerns about students who might fall in the "gap" between the regular assessment and the alternate assessment based on alternate achievement standards (AA-AAS), the U.S. Department of Education announced that states could develop alternate assessments based on modified achievement standards (AA-MAS). This article reports empirical evidence on characteristics of students participating in the AA-MAS, how students were assigned to test types, research on changes in assessment designs over a 4-year period, and changes in rates of participation and proficiency. The results suggest states and districts have struggled with how to appropriately assign students to this test option, and that there is a need to ensure this group of students has access to rigorous standards-based content. It concludes with a discussion of what can be learned from this policy attempt to resolve a very real problem as the United States moves toward the next generation of assessments.