Retrieval practice (the testing effect)
Quizzing boosts classroom learning: a meta-analysis of 222 studies
In short: Across 222 studies in real classrooms with 48,478 students, low-stakes quizzing improved achievement by a medium amount compared with restudying and other strategies. Feedback, repeated quizzes and quiz questions that match the final test all changed how big the benefit was.
| Paper | Testing (quizzing) boosts classroom learning: A systematic and meta-analytic review |
| Authors | Chunliang Yang, Liang Luo, Miguel A. Vadillo, Rongjun Yu, David R. Shanks |
| Published | April 2021 · Psychological Bulletin 147(4), 399–435 |
| Study type | Systematic review and meta-analysis · Peer-reviewed |
| What we read | Abstract only. Summary based on the published abstract only. |
| Summarized |
What they did
The authors pooled data from 222 independent classroom studies of the "testing effect" and analysed what made the effect larger or smaller.
Who took part
48,478 students across the included studies.
What they found
- Quizzing raised academic achievement by a medium amount overall.
- The size of the benefit depended on what it was compared with, whether quiz and final test formats matched, whether the material matched, corrective feedback, number of quiz repetitions, where and when quizzes were given, how long the treatment lasted and the study design.
- The authors see support for three explanations: extra exposure to the material, practising the kind of thinking the test needs, and motivation.
Effect size: Overall g = 0.499.
Limitations
- A meta-analysis is only as good as the studies it pools, and studies varied a lot.
- We read only the abstract, so we don't report the size of each moderator here.
What this means for learners and parents
- Short, low-stakes quizzes beat rereading notes. That holds in classrooms, not only labs.
- Check answers after quizzing, and quiz more than once.
- At home: turn notes into questions and answer them before looking.
Put it into practice (free tools)
Citation
Chunliang Yang, Liang Luo, Miguel A. Vadillo, Rongjun Yu, David R. Shanks (2021). Testing (quizzing) boosts classroom learning: A systematic and meta-analytic review. Psychological Bulletin 147(4), 399–435. https://doi.org/10.1037/bul0000309
Related summaries
- The classic study: testing yourself beats rereading after a week · Henry L. Roediger III et al., 2006 · Lab experiments