# Spaced repetition
Spaced repetition using flashcards is one of the most effective methods to memorize things. If you want to learn more about it, you can start on [article on Wikipedia](https://en.wikipedia.org/wiki/Spaced_repetition) or check out [this wonderful comic strip](https://ncase.me/remember/) from Nicky Case.
### Recall level
Every card detected in your notes has a so called “recall level” associated with it which indicates how well you remember it. It also represents the number of days after which it will be queued for review again.
### Multipliers
When you are testing yourself, the recall level changes based on how well you remember the card. The theory is simple - if you remember it well the recall level goes up, otherwise it goes down.
**Recall** uses a simple algorithm and multiplies the current recall level by a constant and there’s a constant defined in your configuration for each of the review results. By default, these constants are 2, 0.5 and 0, which in practice means that
* if you click Remembered, the recall level will be doubled;
* and if you click Struggled, the recall level will be halved;
* if you click Forgot, the recall level will go back to 1 (minimum value).
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