Peer teaching involves students teaching other students and has been used since 1795 when it was first organized as a theory by Andrew Bell. Peer teaching can be defined by the relationship between teacher and student, with peers generally being equal in rank or experience. In peer teaching, students take on roles as pure teachers, mediators, work partners, or role models for other students. Some advantages of peer teaching include giving students more individualized learning time, promoting active learning through student interaction, reinforcing learning as students teach others, and providing a financially efficient alternative to hiring more teachers. However, peer teachers require support and advice, and an initial group is needed to start peer teaching activities.