# Interval

(Redirected from Inter-repetition interval)

**Interval** in SuperMemo is a period of time between two reviews of the same piece of knowledge. Spaced repetition algorithm used in SuperMemo attempts to determine optimum interval, i.e. the interval that matches chosen optimization criteria. In the default case, SuperMemo chooses **optimum interval** to represent review that ensures 90% chance of recall.

For more see: Optimum interval.

This glossary entry is used to explain SuperMemo, a pioneer of spaced repetition software since 1987