# Difference between revisions of "Glossary:Difficulty"

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− | '''difficulty''' - estimation of element difficulty in '''SuperMemo'''. Two measures can be used to express '''difficulty''': | + | '''difficulty''' - estimation of [[Glossary:Element|'''element''']] difficulty in '''SuperMemo'''. Two measures can be used to express '''difficulty''': |

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+ | # current estimation of '''element'''<nowiki>'</nowiki>s absolute difficulty is represented by [[Glossary:A-Factor|'''A-Factor''']] (this measure determines the next '''inter-repetition interval''' for items), and | ||

+ | # heuristic measure of difficulty based on the history of repetitions and displayed in the [[element data window]] as '''Difficulty''' (this measure can be used to sort collections that are to be used by other users; starting with easy items first). | ||

+ | |||

+ | An item that is initially difficult (low '''A-Factor''') can become easy to recall once a strong memory imprint is formed. Such an item may quickly reach a relatively high value of '''A-Factor''' that reflects current recall difficulty. On the other hand, the '''Difficulty''' parameter takes into account, apart from '''A-Factor''', such parameters as the number of lapses, current interval, etc. If an item reaches a long interval on poor grades, it will have a low '''A-Factor''' but may have a high '''Difficulty'''. At the same time, an item forgotten many times may suddenly reach a high '''A-Factor''' while its '''Difficulty''' still remains high. '''Difficulty''' is expressed as percentage with 0% standing for easiest possible items, and 100% for the most difficult items. '''A-Factors''' may be considered as the difficulty from the point of view of [http://supermemo.com/english/algsm11.htm SuperMemo Algorithm], while '''Difficulty''' is closer to expressing what the user views as the difficulty of learning a given '''element''' (to see components of '''Difficulty[2]''' press ''Ctrl+Shift+P'' and click '''Difficulty''') |

## Revision as of 07:57, 9 April 2011

**difficulty** - estimation of **element** difficulty in **SuperMemo**. Two measures can be used to express **difficulty**:

- current estimation of
**element**'s absolute difficulty is represented by**A-Factor**(this measure determines the next**inter-repetition interval**for items), and - heuristic measure of difficulty based on the history of repetitions and displayed in the element data window as
**Difficulty**(this measure can be used to sort collections that are to be used by other users; starting with easy items first).

An item that is initially difficult (low **A-Factor**) can become easy to recall once a strong memory imprint is formed. Such an item may quickly reach a relatively high value of **A-Factor** that reflects current recall difficulty. On the other hand, the **Difficulty** parameter takes into account, apart from **A-Factor**, such parameters as the number of lapses, current interval, etc. If an item reaches a long interval on poor grades, it will have a low **A-Factor** but may have a high **Difficulty**. At the same time, an item forgotten many times may suddenly reach a high **A-Factor** while its **Difficulty** still remains high. **Difficulty** is expressed as percentage with 0% standing for easiest possible items, and 100% for the most difficult items. **A-Factors** may be considered as the difficulty from the point of view of SuperMemo Algorithm, while **Difficulty** is closer to expressing what the user views as the difficulty of learning a given **element** (to see components of **Difficulty[2]** press *Ctrl+Shift+P* and click **Difficulty**)