An online school (virtual school or cyber-school) teaches students entirely or primarily online or through the internet. An online school can mimic many of the benefits provided by a physical school (learning materials, online exercises, self-paced courses, live online classes, tests, web forums, etc) but delivers these through the internet. Physical interaction by students and teachers is unnecessary, or only supplementary. Online schools may also enable individuals to earn transferable credits or to take recognised examinations, to advance to the next level of education.
Instructional models vary, ranging from distance learning types which provides study materials for independent self-paced study (asynchronous), to live, interactive classes where students or pupils work with a teacher in a class group lesson (synchronous). Class sizes range widely from a small group of 6 pupils or students, to hundreds Live lessons with personal interaction (synchronous learning) necessarily run on small groups of 6 - 30, while distance learning (asynchronous learning) can be any number, and may be very large.
It can often be assumed that there is a lack of social communication in an online school, therefore for younger students (pupils) a concern for lack of social skills training. The distance learning model where study packages are sent out, does fit this assumption, as the only human interaction is the marking of work by a teacher, and even that much may not be part of the service. But in a live, interactive, online school (synchronous learning) lessons are socially constructed. Students or pupils are in contact with each other and with teachers through software provided by the online school, and by email, both in lessons and outside them. Students can also communicate by phone, where permitted. Through the various kinds of social contact personal relationships develop. Some online schools do specifically address personal and welfare support, especially in the case of younger students (pupils) for social skills training, both in its own right and to underpin effective, orderly lessons.
The mid-1990s saw the advent of completely virtual schools. Many of today's virtual schools are descendants of correspondence schools. The earlier online schools began in Australia, New Zealand, North America and the UK, generally in areas where low density population made schooling by conventional means difficult and expensive to provide. In 2008 an assessment found high dropout rates. As in other computerised environments, once the glamour of the new methods wore off it became clear that human skills were paramount to success, in this case teaching and welfare expertise. Where this is recognised retention is good, i.e. in the synchronous, socially structured models; in the huge MOOC style courses the same isolation problems as correspondence learning are found.
Sometimes referred to as "distance learning", correspondence schools offered students an alternative to the traditional brick and mortar meetings within a schoolhouse. These schools utilized the postal service for student-teacher interaction, or used two-way radio transmissions, sometimes with pre-recorded television broadcasts. Students were expected to study their learning material independently and, in some cases, meet with a proctor to be tested.