Editing Spaced repetition (section)

=== Paper flash cards ===
{{Anchor|Flash cards|reason=Old, ambiguous section title; may have incoming links.}}
[[File:Leitner_system_animation.gif|right|thumb|250px|Animation of three sessions]]
The [[Leitner system]] is a widely used method of efficiently using [[flashcard]]s that was proposed by the German science journalist [[Sebastian Leitner]] in the 1970s. It is a simple implementation of the principle of spaced repetition, where cards are reviewed at increasing intervals.

In this method, flashcards are sorted into groups according to how well the learner knows each one in Leitner's learning box. The learners try to recall the solution written on a flashcard. If they succeed, they send the card to the next group. If they fail, they send it back to the first group. Each succeeding group has a longer period of time before the learner is required to revisit the cards. In Leitner's original method, published in his book ''{{lang|de|So lernt man Lernen}}'' (''How To Learn To Learn''), the schedule of repetition was governed by the size of the partitions in the learning box. These were 1, 2, 5, 8 and 14&nbsp;cm. Only when a partition became full was the learner to review some of the cards it contained, moving them forward or back, depending on whether they remembered them.