Card scheduling
Recall uses spaced repetition to help you remember more information in significantly less time.
The algorithm
Learning phase
When a card is new, it uses fixed short-term intervals before entering the review phase. Once you've pressed "Good" twice in a row or "Easy" once, the card moves to the review phase.
Review phase
Recall uses the open-source Free Spaced Repetition Scheduler (FSRS) version 4.5 to schedule cards in the review phase.
The goal of FSRS is to predict when the retention of a card reaches a target level, so that you review it at the right time. It has been shown to significantly outperform other spaced repetition algorithms (source).
Study pace
You can change the Daily new reviews and Target retention settings to adjust your study pace. They both live in your deck's tab.
Daily new reviews
This is the maximum number of card variants added to the reviews each day. Fewer reviews are scheduled if you already have many reviews due, such as:
Total number of due reviews of the day < Daily new reviews * 4
Target retention
This is the minimum percentage of cards of your deck that you want to remember at any given time.
The target retention can be set between 70% and 99%. Keep in mind that each additional percentage point over 95% significantly increases the number of reviews.
When you update the target retention, the change is taken into account to calculate the next intervals when you review new cards. It doesn't reschedule all your cards retroactively.
Study order
In your deck's tab, you can also indicate in which order you wish new cards to be introduced.
New cards order
There are three possible ways to order new cards:
- Default: The cards are shown in the order they were created.
- Random order: The cards are ordered randomly.
- Field value: The cards are ordered by the value of a number field contained in the deck. For example, you could have a frequency field in a vocabulary deck, and get the most frequent words first.
Layouts sequence
You can choose to have card variants scheduled randomly or in a specific order.
Whenever possible, variants of the same card are scheduled with a minimum interval of 1 day between them.
Pause study
If you want to stop studying a deck temporarily, you can use the Pause study setting in your deck's tab.
When a deck is paused, the reviews due no longer appear in the app (home, decks list, side menu, etc.). The deck is also ignored for daily due email and push notifications.
While a deck is paused, new cards are not added to reviews. Already scheduled cards are not affected; due cards will immediately reappear when you unpause the deck.
Scheduling or unscheduling cards manually
You can manually schedule or unschedule cards.
- On the main page of a deck, click on the row of a card.
- In the card detail panel, click in the top right corner of the panel.
- During a review, click in the top right corner of the page.
When a card is unscheduled, it's eligible to be automatically added to reviews again after 7 days.
When you schedule or unschedule an individual card, all variants of the card are affected.
Study more
Once you have reviewed all your due cards and unscheduled cards are available, a Study more link next to the study button on the deck's page will appear. It allows you to immediately schedule up to 50 card variants.