# Active Recall and Flashcards: How to Revise So It Sticks

> Why testing yourself beats re-reading, how spaced repetition decides when to revise, and how to write flashcards that test understanding rather than memorised wording.

Two ideas from learning research change how most people revise. **Active recall**: pulling an answer out of memory strengthens it far more than reading it again. **Spacing**: revising just as you are about to forget beats revising the same thing three times in one evening.

Flashcards are the simplest tool that uses both, provided the cards are written well.

## Why re-reading feels good and works badly

Re-reading makes material familiar, and familiarity feels like knowing. Then the exam asks you to produce the answer with nothing in front of you, which is a different skill. Recall practice trains exactly that skill: every time you retrieve an answer, the next retrieval gets easier.

Getting an answer wrong while practising is not wasted time. A failed attempt followed by the correct answer is one of the strongest ways to learn it.

## A revision schedule that respects forgetting

| When | What to do |
| --- | --- |
| Same day | Finish the level and answer its checkpoint from memory |
| Next day | Run the flashcards once; set aside the ones you missed |
| After a week | Run the missed cards, then the full deck |
| After a month | Full deck once; anything missed goes back to the one-day slot |

Cards you know well drift to longer gaps; cards you miss come back sooner. That is all spaced repetition is.

## How to write a good flashcard

- **One idea per card.** A card with three facts on it is three cards.
- **Ask for the reason, not only the word.** "Why does a dictionary lookup stay fast as it grows?" beats "What is a hash map?"
- **Use the real topic, not an analogy.** Analogies help you learn; the exam asks about the thing itself.
- **Answer out loud or in writing before you flip.** Thinking "I know this" does not count.
- **Keep the answer short.** If the answer is a paragraph, the question is too big.

## How many cards per level?

Enough to cover what the level taught and no more. For a level of three lessons that is usually ten to twenty cards. A deck you finish every day beats a perfect deck you never open.

## Flashcards in LoWisa

Every level in the LoWisa app ends with a checkpoint and a deck of flashcards on the topics that level covered. The deck has a sensible default size for the lessons you completed, and you can choose a different number. Cards test the real topics, not the analogies used to teach them. The app is on Google Play and the App Store; see [Checkpoints and flashcards](/help/checkpoints-and-flashcards/) for how they work in the app.

## Frequently asked questions

### What is active recall?

Active recall means answering from memory instead of re-reading. Each retrieval strengthens the memory, which is why self-testing outperforms re-reading for exams.

### What is spaced repetition?

Spaced repetition schedules revision at growing intervals, such as one day, one week and one month, so you revise each item just before you would forget it.

### How many flashcards should I make per topic?

Enough to cover the ideas the topic taught, usually ten to twenty for a short level. One idea per card, with short answers.

### Are flashcards good for understanding, or only memorising?

Both, if the cards ask why and how rather than only what. A card that asks for a reason tests understanding.

## Revise with checkpoints and flashcards

Every LoWisa level ends with a checkpoint and a flashcard deck on what you just learned.

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Source: https://lowisa.dev/learn/active-recall-flashcards/ · Updated 2026-09-27