Most students study by rereading notes and highlighting textbooks. It feels productive because the material starts to look familiar. But recognizing something on the page is not the same as being able to produce it in an exam, and that sense of familiarity fades within days.
Two techniques do much better, and they have been tested in laboratories and classrooms for decades.
What the research says
In 2013, a team of psychologists led by John Dunlosky reviewed the evidence for ten popular study techniques (Dunlosky et al., 2013). Only two earned their top rating of “high utility”: practice testing and distributed practice — what most students now call active recall and spaced repetition. Rereading and highlighting, two of the most common study habits, were rated “low utility”.
A classic experiment shows why (Roediger & Karpicke, 2006). Students read short prose passages and then either reread them or took a test in which they wrote down as much as they could remember. On a final test five minutes later, the rereaders did slightly better. But when the final test came two days or a week later, the students who had practiced recalling remembered considerably more. Studying that feels effective in the moment is not always the kind that lasts.
Spacing has an equally long record. A review of more than 300 experiments found that spreading study sessions out produces better long-term memory than packing the same amount of study into one block (Cepeda et al., 2006).
What active recall looks like
Active recall is any study activity that makes you answer before you see the answer:
- Close your notes and write down everything you remember about a topic, then check what you missed.
- Turn each heading in your notes into a question and answer it out loud.
- Use flashcards, and say the answer before you flip the card.
- Do practice problems or past exam questions without looking at the worked solutions first.
- Explain a concept to a friend — or to an empty room — without notes.
How to space your reviews
There is no single perfect schedule. The general rule from the research: come back to material as it starts to fade, and let the gaps grow as it gets easier to remember. The longer you need to remember something, the longer the gaps between reviews can be.
A simple starting point for a new topic:
| Review | When | What to do |
|---|---|---|
| 1 | Same day | Write down what you remember from the lecture, then check your notes |
| 2 | Next day | Answer 10–15 questions or flashcards |
| 3 | About 3 days later | Mixed questions, including an older topic |
| 4 | About a week later | Timed practice questions |
| 5 | 2–3 weeks later | A past paper or full problem set |
Flashcard apps such as Anki handle the scheduling for you: cards you answer easily come back less often, and cards you miss come back sooner.
Common mistakes
- Making cards that are too big. One fact or idea per card. “Explain the causes of the First World War” is an essay question, not a flashcard.
- Copying from the textbook. Write questions and answers in your own words. Doing that forces you to understand the idea first.
- Recognizing instead of recalling. Picking an answer from a list is better than nothing, but producing an answer from memory usually does more.
- Only testing yourself on what you know. It feels good, but the questions you keep getting wrong are the ones that need your time.
- Letting reviews pile up. A missed day is fine. A missed week turns into a backlog. Keep daily sessions short enough to survive busy weeks.
Add interleaving once you’re comfortable
When both habits feel routine, try mixing topics within a session — for example, alternating between different types of math problems instead of doing twenty of the same kind in a row. This is called interleaving. The 2013 review rated it “moderate utility”: the evidence is promising, especially for math, but less extensive than for testing and spacing.
How to start this week
Pick one course. After each lecture, spend ten minutes writing questions about what you just learned. Answer them without notes the next day, again a few days later and again the following week. Check every answer, and mark the ones you missed so they come back sooner.
It will feel slower than rereading at first. That is the point: the extra effort is the learning.
Frequently asked questions
What is the difference between active recall and spaced repetition?
Active recall is how you study: pulling information out of memory, for example by answering questions without looking at your notes. Spaced repetition is when you study: reviewing the same material several times, with growing gaps in between. They work best together.
Is active recall better than rereading?
For long-term memory, yes. In a well-known experiment, students who reread a passage did slightly better on a test five minutes later, but students who practiced recalling it remembered considerably more two days and a week later. A 2013 review rated practice testing high utility and rereading low utility.
How long should the gaps between reviews be?
There is no single perfect schedule. A practical starting point is to review the same day, the next day, about three days later, about a week later and two to three weeks later. The longer you need to remember something, the longer the gaps can be.
Do I need an app like Anki for spaced repetition?
No. Paper flashcards, lists of questions and past papers all work. Apps such as Anki automate the scheduling, showing cards you find easy less often and cards you miss sooner.
