What a Spaced Repetition App Does
Spaced repetition means reviewing something at growing intervals — a day, then a few days, then a week, then a month — instead of all at once. Each review comes just as the memory is starting to fade, which is when reviewing does the most good.
Doing that by hand for hundreds of ideas is impossible. A spaced repetition app does the bookkeeping. It tracks every item, decides when each one is due, and shows you only those today.
The idea is old. Piotr Woźniak built SuperMemo, the first spaced repetition software, in 1987. Most apps since then use a descendant of his scheduling method, and some now use newer, data-trained schedulers.
The Five Things That Actually Matter
1. Who makes the cards
This is the biggest difference between apps, and the reason most people quit.
In a traditional flashcard app, you write every question yourself. That has a real benefit — writing a good question is itself a way of learning. But it is slow. Turning one book chapter into good cards can take longer than reading it. Most people who abandon spaced repetition abandon it here, not at the reviewing.
Newer apps generate the questions from your material. The trade-off is control: you need to trust that the app chose the right ideas and asked about them well.
Ask: will I realistically make cards for everything I want to keep? If not, card-making is your bottleneck, and the app should solve it.
2. Does it test recall or recognition?
Spaced repetition only works if each review makes you produce the answer. A card you glance at and flip is recognition, not recall, and it builds far less memory.
Look for apps that make you commit to an answer before showing it, or ask questions you have to work out rather than just remember word-for-word.
3. Does it go beyond facts?
Flashcards are excellent for facts with one right answer: a word, a date, a dose, a definition. They are weak for ideas you need to use — a framework, an argument, a way of thinking.
Knowing the definition of a concept and being able to apply it to a new situation are separate skills. If you learn from books and articles for work, an app that only asks "what is X?" will make you good at definitions and nothing more.
A flashcard can tell you whether you remember an idea. It cannot tell you whether you can use it.
4. How does it choose what to keep?
An app that turns everything you read into cards will bury you. Ten articles become three hundred cards, the daily review climbs past an hour, and you stop.
Good apps help you keep less. They pick the central ideas and leave out asides, examples and filler, or let you choose quickly what goes in.
5. Will you still open it in three months?
The best scheduler in the world is useless if you stop reviewing. Daily review time that stays under fifteen minutes, sessions you can do on your phone, and a pile of due items that does not punish you for missing a day matter more than any feature list.
Which Kind of App Fits You
If you are memorising set facts: a flashcard app
Languages, medicine, law, exam syllabuses, anything with a fixed body of facts. Here the classic flashcard apps shine.
- Anki — free on desktop and Android, with a paid iPhone app. Extremely flexible, with a large library of shared decks. The interface takes some learning, and you build or import your own cards.
- SuperMemo — the original, with a long history of scheduling research behind it.
- Notes-plus-flashcards tools such as RemNote, which let you turn notes into cards as you write them.
If you are happy writing cards, or a good shared deck already exists for your subject, start here.
If you want to keep highlights: a resurfacing tool
Tools that collect your highlights from books and articles and show you a few each day are pleasant and easy to keep up. Be clear about what they do, though: mostly they show you the highlight again, which is re-reading, not recall. Some offer features that turn highlights into questions, which is worth switching on.
If you want to remember and use what you read: a reading-first app
If you read books, articles and reports for work, and the goal is to use the ideas in decisions rather than pass a test, you need something different. You need the app to pull out the key concepts for you, ask about them without you writing anything, and move beyond "what is it?" to "which idea fits this situation?" and "where does it break?"
That is the gap LearnBetter was built for — see how it scores on the checklist below, or read how LearnBetter works.
A Quick Checklist
- Do I have to write the cards, and will I really do that?
- Does each review make me produce an answer before I see it?
- Does it test whether I can use ideas, or only state them?
- Does it help me keep fewer, better items?
- Will my daily review stay under fifteen minutes?
Answer those honestly and the right kind of app is usually obvious. The scheduler, almost always, is the least important part.
The best spaced repetition app is the one you are still using in six months.
How LearnBetter Scores on the Checklist
Here is how LearnBetter answers the five questions above, so you can judge it the same way as any other app.
- Who makes the cards? It does. Add an article link, a PDF or ebook, a Word document, a YouTube video or pasted text, and it writes the questions from the material.
- Recall or recognition? Recall. You answer before you see the answer.
- Beyond facts? Yes. Questions climb from remembering a concept to applying it, analysing it and judging when it fits — and it tracks how well you remember and how well you can use each concept separately.
- Keeping fewer items? It picks out the key concepts from each reading and groups them into topics. For a long book, you can choose which chapters to start with.
- Scheduling? FSRS, a modern spaced-repetition scheduler, brings each concept back just before you would forget it.
Where it is not the right tool: if you need to memorise a fixed list of vocabulary or exam facts, a flashcard app like Anki is still the better fit. LearnBetter is built for the ideas in what you read.
This article is part of our guide to how to learn better — six science-backed habits for remembering and using what you read.
Frequently Asked Questions
A spaced repetition app tracks what you are learning and shows each item again at growing intervals — just before you are likely to forget it — so you keep it with the least possible review time.
It depends on what you are learning. For fixed facts such as vocabulary or medical terms, a flashcard app like Anki is hard to beat. For remembering and applying what you read — books, articles, reports — an app that builds questions from your reading for you is a better fit.
Anki schedules reviews very well, but you have to write every card yourself. For a book or a stack of articles, that card-making usually takes longer than the reading, which is where most people give up.
Yes, when each review makes you produce the answer rather than just recognise it. Spacing reviews over time is one of the two study methods rated most effective in a major 2013 review of learning techniques.
For most people, ten to fifteen minutes is sustainable. If your daily reviews climb well beyond that, you are probably keeping too many items, and the habit is at risk.
Classic flashcards test whether you can recall a fact, not whether you can use it. To build application, look for an app that asks you to choose which idea fits a new situation, or to spot where an idea breaks down.
Sources
- Woźniak, P.A. & Gorzelańczyk, E.J. (1994). Optimization of repetition spacing in the practice of learning. Acta Neurobiologiae Experimentalis, 54, 59–62.
- Cepeda, N.J., Pashler, H., Vul, E., Wixted, J.T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354–380.
- Kornell, N. (2009). Optimising learning using flashcards: Spacing is more effective than cramming. Applied Cognitive Psychology, 23(9), 1297–1317.
- Roediger, H.L. & Karpicke, J.D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249–255.
- Dunlosky, J., Rawson, K.A., Marsh, E.J., Nathan, M.J., & Willingham, D.T. (2013). Improving students' learning with effective learning techniques. Psychological Science in the Public Interest, 14(1), 4–58.
- Brown, P.C., Roediger, H.L., & McDaniel, M.A. (2014). Make It Stick: The Science of Successful Learning. Harvard University Press.
Spaced repetition for what you read
LearnBetter builds the questions from your books and articles for you — recall and application — and schedules each one just before you'd forget it. Free to start.
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