Alternative education, also known as non-traditional education or educational alternative, includes a number of approaches to teaching and learning other than mainstream or traditional education. Educational alternatives are often rooted in various philosophies that are fundamentally different from those of mainstream or traditional education. While some have strong political, scholarly, or philosophical orientations, others are more informal associations of teachers and students dissatisfied with some aspect of mainstream or traditional education. Educational alternatives, which include charter schools, alternative schools, independent schools, and home-based learning vary widely, but often emphasize the value of small class size, close relationships between students and teachers, and a sense of community.