Glossary:E-Factor

E-Factor (also: easiness factor or EF) (in early versions of SuperMemo, up to and including SuperMemo 7) - a number related to the difficulty of a given element. In the earliest versions of SuperMemo (up to and including SuperMemo 3), new inter-repetition interval was determined by multiplying the old interval by E-Factor. A-Factors associated with topics and tasks are used in the same way as early E-Factors, i.e. to determine the value of the new interval by multiplying the A-Factor by the old interval. To better understand the role of A-Factors in new versions of SuperMemo, see: Incremental reading