Outcome-based education (OBE) is education in which an emphasis is placed on a clearly articulated idea of what students are expected to know and be able to do, that is, what skills and knowledge they need to have, when they leave the college system. It is sometimes also called performance-based education and is an attempt to measure educational effectiveness based on results rather than on inputs such as time students spend in class. The student learning outcomes constitute the criteria by which curriculum is developed or redesigned, instructional materials are selected, teaching methods are adopted, and evaluation is conducted.