Review at the right time: how to plan spaced repetition
You read the chapter carefully three weeks ago. Now, with the exam getting closer, it feels almost new. That does not mean you studied the wrong way; memory simply needs several encounters with the material. The question is when those encounters should happen.
The Aria editorial team · 6 min read · For students who want to remember their syllabus until the exam without rereading everything in the final week.
Spaced repetition means returning to a topic several times with growing gaps, instead of studying everything at once. It often leads to more lasting learning. Review by recalling the answer yourself, and make the interval longer when you remember and shorter when you miss.
Why material fades after a few weeks
Forgetting is not a sign that you are bad at learning. It is a normal part of how memory works. In 2015, Murre and Dros repeated Ebbinghaus’ classic experiment and found the same pattern: a lot fades fairly quickly after first learning, then the curve levels out. The study was small and used nonsense syllables, so the numbers cannot be applied directly to a syllabus.
The practical point is still clear. If you study a topic once and do not see it again until exam week, you largely have to learn it again. If you return to it while you still remember some of it, each round becomes shorter and the knowledge more stable.
Spaced repetition or cramming
Cramming can feel like control the day before a test, because the material is fresh. The problem is that it often fades quickly afterwards. In 2008, Cepeda and colleagues tested more than a thousand participants with different gaps between learning and review. Those who spaced their reviews remembered more at the final test than those who reviewed close together, and the best gap grew longer the further away the test was.
The study dealt with factual knowledge, and the results are group averages. It therefore does not give an exact formula for your subject. It does give a useful rule of thumb: if you need to remember something in several weeks, your reviews should also be spread over several days and weeks.
Cramming
- Rereads the whole topic several times the night before.
- Feels confident because the text seems familiar.
- Has to relearn a lot before the next test.
Spaced repetition
- Spreads shorter sessions over several weeks.
- Notices which parts have actually stuck.
- Uses the final week to apply the material.
Review by recalling the answer yourself
It is not only when you review that matters, but also how. Rereading your notes feels comfortable but says little about whether you can use the material. In 2008, Karpicke and Roediger found that students who repeatedly had to retrieve word pairs from memory remembered far more a week later than those who simply studied the pairs again.
The experiment used vocabulary, so the effect will vary with subject and task type. The principle is still easy to apply: ask yourself a question, answer before you look and check your answer against the syllabus. Flashcards, glossaries and short practice tests work well because they make you answer first.
How to choose intervals in practice
There is no single right interval for everyone. A simple starting point is to review the first time after a few days, then let the gap grow when the answer sticks. If you miss, the topic comes back sooner. That way you spend most time on what is uncertain and less on what you already know.
- Create questions on the topic the same day or the day after you learn it, for example as flashcards or a glossary.
- Review the first time after a few days by answering yourself before you check the answer.
- Make the next gap longer for what you remembered, and shorter for what you missed.
- Keep going until the exam so every topic gets several rounds. In Aria, flashcard decks and glossaries get a new review date after each practice.
Towards the exam
Spaced repetition works best when you start early. With eight weeks left, every topic gets many rounds. With ten days left, it is still useful to spread your reviews over several days, but you need to prioritise what matters most and what you are least sure about.
Reviewing facts and concepts is not the whole of exam preparation. Many exams ask you to discuss, calculate or apply theory to a new case. Use the final weeks for exam-style tasks as well, so you practise using what you remember. Spaced review makes sure the foundation is in place when you need it.
When the plan slips
Do not let the plan become a new source of stress. If you miss a review, simply take it next time. What matters most is that you meet the material several times, not that every date is followed exactly.
It is common for a week to get busier than planned. A short round with the cards you missed most is then better than skipping everything or trying to catch up in one evening.
Do this now
- Plan the first review a few days after you learned the material.
- Review by answering yourself before you check the answer.
- Make the interval longer when you remember and shorter when you miss.
- Start early enough for every topic to get several rounds.
Frequently asked questions
What is spaced repetition?
It means returning to the same material several times with gaps in between, instead of studying it all at once. The gap usually grows as you remember the material.
How long should I wait before the first review?
There is no fixed answer, but a few days is a good starting point. The further away the exam is, the longer the gaps can become over time.
Is it too late to start a week before the exam?
No. Spread your reviews over the days you have, prioritise what matters most and use active recall. The effect is larger when you start earlier.
Does Aria plan my reviews for me?
Aria suggests a new review date for flashcard decks and glossaries after you practise. You decide when to practise, and the suggestions are a guide.
Sources
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