In the original process, a teacher was asked to prepare a short lesson (usually 20 minutes) for a small group of learners who may not have been his/her own students.
Watching the video and getting comments from colleagues and students provide teachers with an often intense "under the microscope" view of their teaching.
A review of the evidence for micro-teaching, undertaken by John Hattie as part of his Visible Learning project, found it was the 6th most effective method for improving student outcomes.
In more recent years, the easy availability of recording equipment and the use of social media for dissemination have made micro-teaching more accessible.
The built-in feedback mechanism in micro-teaching acquaints the trainee with the success of their performance and enables them to evaluate and to improve teaching.