Spaced practice vs massed practice (cramming): which works better?
Spacing wins for long-term memory. A meta-analysis of 29 studies found spreading retrieval practice out over time led to much better retention than doing the same practice all at once. A synthesis of 317 experiments found the best gap between sessions grows with how long the material must be remembered, and a classroom experiment found fifth graders remembered vocabulary taught a week apart better five weeks later. Massed practice can carry a student through tomorrow's test; spaced practice is what lasts.
| Question | Spaced practice | Massed practice |
|---|---|---|
| Evidence rating in the Library | Strong Practice card | No card yet |
| What it is | Practice and review of the same material spread across days and weeks. | The same amount of practice done in one block, such as a unit's practice in one week or studying the night before. |
| How it feels | Harder: some forgetting between sessions, so each return takes effort. | Smoother: the material is fresh, so practice goes well. |
| Short-term result | Can look worse during practice. | Can look better during practice and on a test soon after. |
| Long-term result | Better retention in the studies cited here. | Worse retention later. |
| Classroom form | Cumulative warm-ups, mixed homework, quizzes on old units, spiral review. | Twenty problems on today's skill; a review day right before the test. |
| Does the exact schedule matter? | Less than having gaps at all: expanding gaps were no better on average than equal gaps in a 2021 meta-analysis. | Not applicable. |
The studies that bear on the choice
Spreading retrieval practice on the same content out over time led to much better retention than doing it all at once. Expanding gaps (short, then longer, then longer) were no better on average than equal gaps, contrary to a widely held belief.
Sample 29 studies; 39 effect sizes for spaced vs massed, 54 for expanding vs uniform schedulesEffect spaced vs massed retrieval practice g = 0.74; expanding vs uniform spacing g = 0.034 (not significant)Read it at the source (opens in a new tab)The best gap between study sessions depended on how long the material had to be remembered: longer retention, longer best gap.
Sample 839 assessments of distributed practice in 317 experiments from 184 articlesRead it at the source (opens in a new tab)Fifth graders taught unfamiliar English words in two sessions a week apart remembered more of them five weeks later than when the same teaching was crammed into one session, showing the spacing effect in a real classroom with school-age children.
Sample 39 fifth graders in their own classroomsWho School-age childrenRead it at the source (opens in a new tab)Hundreds of studies show that spacing out repeated encounters with material produces better long-term learning than massing them, and adding tests to spaced practice increases the benefit. Spaced practice helps memory, problem solving and applying learning to new situations, and is cheap and feasible for schools.
A review for teachers: final test performance improves when study sessions are spaced apart rather than massed together. It covers which kinds of learning benefit, demonstrations in real educational settings, and how far apart sessions should be, and ends with recommendations for building spacing into everyday teaching.
What the research found
Alice Latimier, Hugo Peyre and Franck Ramus pooled 29 studies of retrieval practice and found that spacing practice sessions apart produced much better retention than massing them together. They also found no advantage, on average, for gaps that grow over time compared with equal gaps.
Nicholas Cepeda and colleagues' synthesis of 317 experiments found that the gap between sessions and the time until the test work together: material needed for longer needs longer gaps. Hailey Sobel and colleagues showed the effect in fifth-grade classrooms with vocabulary. Reviews for teachers by Sean Kang and by Shana Carpenter and colleagues summarize a large body of research showing spacing helps long-term learning in educational settings.
Does cramming ever make sense?
For a test tomorrow on material you'll never need again, cramming can get a student through. But school knowledge builds on itself: fractions are needed for algebra, vocabulary for every later text. For anything that matters later, the research favors spacing.
Massed practice has a second problem: it produces a false sense of mastery. Twenty problems in a row on one skill feel easy by the end, which is not the same as being able to do one cold next month.
The same practice, two schedules
A fourth-grade class learns multiplying by two-digit numbers. Massed: forty problems over two days in the week it's taught, then the class moves on to division. Spaced: fifteen problems in the week it's taught, then five in each of the next five weeks' homework, mixed with other skills, and two on each later unit quiz.
The total practice is the same. In the massed version, students look fluent by the end of the second day and much of it is gone by the end of term. In the spaced version, practice feels harder each time, because students have partly forgotten, and that effortful return is what the spacing research credits for the better long-term memory.
For teachers, the main cost of spacing is planning: keeping track of which skills come back when. A simple grid of units and weeks, with a mark for each planned return, is enough, and it can be shared across a grade team.
How to switch from massed to spaced
- Split homework: half on today's skill, half mixed from earlier units. The math worksheet generator helps.
- Open lessons with one question from yesterday, one from last week, one from last month.
- Quiz old units a few weeks after they end, low stakes.
- Give students a study calendar before tests that spreads study over several days.
- Use flashcards with piles reviewed at different intervals.
Questions teachers ask
- How long should the gaps be?
- Longer for material needed longer. As a rough guide, a day or two apart for next week's test, weeks apart for end-of-year material. Cepeda and colleagues found the best gap grows with the retention interval.
- Doesn't spacing take more time?
- No, if it replaces massed practice. The same minutes, spread out, give better long-term retention.
- What about the night before a test?
- A short final self-test the night before is fine, and it's a form of retrieval practice. The problem is when the night before is the only study. Spread most of it over the days before, and make the last session a check, not the first look.
- Is spaced practice the same as interleaving?
- No. Spacing spreads practice of the same material over time; interleaving mixes different kinds of problems in one session. A cumulative worksheet often does both, but they're separate techniques.
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Written by Peabody Teach from the sources above, read at the source. Something wrong? Tell us.