Editing Spaced repetition (section)

== Implementations ==
===Software===
{{see also|List of flashcard software}}
[[File:Anki 2.0.22 KDE4.en.story-ru-en.smallwindow.png|thumbnail|[[Anki (software)|Anki]] being used for memorizing Russian vocabulary]]
Most spaced repetition software (SRS) is modeled after the manual style of learning with physical [[flashcard]]s: items to memorize are entered into the program as question-answer pairs. When a pair is due to be reviewed, the question is displayed on a screen, and the user must attempt to answer. After answering, the user manually reveals the answer and then tells the program (subjectively) how difficult answering was. The program schedules pairs based on spaced repetition [[algorithm]]s. Without a computer program, the user has to schedule physical flashcards; this is time-intensive and limits users to simple algorithms like the Leitner system.<ref>{{Cite news |url=https://www.theguardian.com/education/2016/jan/23/spaced-repetition-a-hack-to-make-your-brain-store-information |title=Spaced repetition: a hack to make your brain store information |last=Gupta |first=James |date=January 23, 2016 |work=The Guardian |access-date=January 30, 2019 |language=en-GB |issn=0261-3077}}</ref>

To optimize review schedules, developments in spaced repetition algorithms focus on predictive modeling. These algorithms use randomly determined equations to determine the most effective timing for review sessions.<ref>{{Cite journal |last1=Tabibian |first1=Behzad |last2=Upadhyay |first2=Utkarsh |last3=De |first3=Abir |last4=Zarezade |first4=Ali |last5=Schölkopf |first5=Bernhard |last6=Gomez-Rodriguez |first6=Manuel |date=2019-03-05 |title=Enhancing human learning via spaced repetition optimization |journal=Proceedings of the National Academy of Sciences |language=en |volume=116 |issue=10 |pages=3988–3993 |doi=10.1073/pnas.1815156116 |doi-access=free |issn=0027-8424 |pmc=6410796 |pmid=30670661|bibcode=2019PNAS..116.3988T }}</ref>

Further refinements with regard to software:
* ''{{vanchor|Confidence-based repetition|reason=[[Confidence-based repetition]] redirects here.}}'': A user rates their confidence in each digital flashcard, e.g. on a scale of 1–5; a lower-confidence card is repeated more frequently until the user upgrades their confidence rating in it.<ref>{{cite web |last=Cohen |first=Andrew S. |title=Confidence-Based Repetition (CBR) |work=Brainscape.com |date=May 12, 2015 |orig-date=2010 |url= https://www.brainscape.com/blog/2010/01/confidence-based-repetition-cbr/ |archive-url= https://web.archive.org/web/20201129231203/https://www.brainscape.com/blog/2010/01/confidence-based-repetition-cbr/ |archive-date=November 29, 2020}}</ref><ref>{{cite web |last=Cohen |first=Andrew S. |title=Brainscape's 'Confidence-Based Repetition' Methodology |work=Brainscape.com |date=July 15, 2008 |url= https://www.brainscape.com/images/cms/research/Confidence-Based_Repetition.pdf |archive-url= https://web.archive.org/web/20201104102529/https://www.brainscape.com/images/cms/research/Confidence-Based_Repetition.pdf |archive-date=November 4, 2020}}</ref>
* Questions and/or answers can be a sound file to train recognition of spoken words.
* Automatic generation of pairs (e.g. for vocabulary, it is useful to generate three question-pairs: ''written foreign word'', its ''pronunciation'' and its ''meaning'', but data only has to be entered once.)
* Additional information retrieved automatically is available, such as example sentences containing a word.
* Opportunities to combine spaced repetition with online community functions, e.g. sharing courses.

=== 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.

=== Audio instruction ===
Graduated-interval recall is a type of spaced repetition published by [[Paul Pimsleur]] in 1967.<ref>{{cite journal
|title=A Memory Schedule
|first=Paul
|last=Pimsleur
|periodical=The Modern Language Journal
|volume=51
|issue=2
|date=February 1967
|pages=73–75
|doi=10.2307/321812
|jstor=321812
|publisher=Blackwell Publishing
}}</ref>  It is used in the [[Pimsleur Language Programs|Pimsleur language learning system]] and is particularly suited to programmed audio instruction due to the very short times (measured in seconds or minutes) between the first few repetitions, as compared to other forms of spaced repetition which may not require such precise timings. The intervals published in Pimsleur's paper were: 5 seconds, 25 seconds, 2 minutes, 10 minutes, 1 hour, 5 hours, 1 day, 5 days, 25 days, 4 months, and 2 years.