Maureen T. Hallinan, past president of the American Sociological Association, past editor of Sociology of Education, member of the National Academy of Education, and prolific scholar, has helped shape the field of sociology of education through her research on student learning and school organization. Her research addresses organizational characteristics, both within (ability grouping) and between schools (Catholic school effects), which helps explain inequality in student outcomes. Hallinan's early work with Aage B. Sorensen addresses three necessary components of student learning: ability, effort, and opportunity to learn. While ability and effort are student characteristics, schools control the opportunities for student learning. Opportunities to learn are situations that provide students with the potential for learning and set the upper limit for the amount of learning that can ...