Leitner system

Flashcard learning technique

The Leitner system is a widely used method of efficiently using flashcards that was proposed by the German science journalist Sebastian Leitner in 1972. 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 before the learner is required to revisit the cards. In Leitner's original method, published in his book 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 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.

Suppose there are 3 boxes of cards called "Box 1", "Box 2" and "Box 3". The cards in Box 1 are the ones that the learner often makes mistakes with, and Box 3 contains the cards that they know very well. They might choose to study the Box 1 cards once a day, Box 2 every 3 days, and Box 3 cards every 5 days. If they look at a card in Box 1 and get the correct answer, they "promote" it to Box 2. A correct answer with a card in Box 2 "promotes" that card to Box 3. If they make a mistake with a card in Box 2 or Box 3, it gets "demoted" to the first box, which forces the learner to study that card more often. The advantage of this method is that the learner can focus on the most difficult flashcards, which remain in the first few groups. The result is, ideally, a reduction in the amount of study time needed.

Ideas similar to these have been implemented into a number of computer assisted language learning and flashcard software. Much of this software makes use of so called "electronic flashcards".