Retrieval practice: why testing yourself beats rereading

The short answer

Trying to recall something, and then checking the answer, makes it stick far better than reading it again. Psychologists call this the testing effect or retrieval practice. In Dunlosky and colleagues’ review of study techniques, practice testing was one of only two rated high utility [1]. A meta-analysis of 222 classroom studies with more than 48,000 students found a reliable benefit of about half a standard deviation (g ≈ 0.50) [2].

The experiment that made the case

Roediger and Karpicke gave 180 students short prose passages [3]. Some read a passage four times. Others read it once and then tried to write down everything they remembered, three times, without being shown the text again.

Five minutes later, the rereaders were ahead: 83% recalled against 71%. One week later the picture reversed. The students who had practiced recalling remembered 61%; the rereaders, 40%. Over that week the rereaders lost about half of what they had recalled at five minutes; the recallers lost about 14%. And the rereaders felt more confident they would remember.

A follow-up with 40 Swahili–English word pairs made the same point more sharply [4]. Every group learned the list perfectly. A week later, students who kept being tested on words they already knew recalled about 80%; students who kept studying those words but stopped being tested on them recalled about a third. Extra study added almost nothing. Extra testing added more than 150%.

Why it feels like the wrong choice

Rereading is smooth. Recalling is effortful, and you notice every gap. That difference in feeling misleads almost everyone. In a survey of 177 college students, 84% reread their notes as a study strategy and 55% named it their main one; only about 1% said self-testing was [5]. Most of those who did test themselves did it to check what they knew, not because they thought it helped them learn.

Students also stop too early. In Kornell and Bjork’s experiment, 63% of the cards students dropped were dropped after a single correct answer, and dropping cards that soon roughly halved later recall [6].

Which kinds of practice work best

• Check the answer. Feedback matters. A week after a multiple-choice quiz, recall was .31 with no feedback, .45 with immediate feedback and .56 with feedback at the end of the quiz [7]. Feedback also cleans up the wrong answers a quiz can plant.
• Recall more than once, and over time. Getting an answer right about three times, then relearning it in about three spaced sessions, is a strong, efficient schedule [8]. See spaced repetition.
• Practice the kind of question you will face. In a classroom study, two quizzes on facts produced 90% on fact questions but only 48% on higher-order ones; two higher-order quizzes produced 85% on higher-order questions and still 53% on facts [9]. In the classroom meta-analysis the testing effect was as large for conceptual material as for facts (0.64 against 0.52) [2].
• Ask about the idea in more than one way. Retrieval helps with new, related questions, but less than with the exact one practiced (d ≈ 0.40 across 192 effect sizes), and most when the practice asks you to elaborate rather than repeat [10]. Three different application questions beat one question asked three times [11].
• Make it a little hard. Cloze-style blanks tend to help with that exact sentence; questions that make you explain or apply reach further [12].

Does testing make you anxious?

Mostly the opposite. In a middle-school science class, 64% of students said regular low-stakes quizzes made them less anxious about exams, and quizzed material scored 92% against 79% on the unit test [13]. A meta-analysis summarized in a 2025 review found that quizzing reduced test anxiety (g = −0.52) [14]. The popular claim that testing makes memories “stress-proof” rests on one study and has not held up in a later meta-analysis [15].

How to use it

1. After a lecture, close the notes and write or say what you remember before you reread anything.
2. Turn the key ideas into questions that ask why and how, not just what.
3. Always check your answer against the source, and grade yourself honestly. Students tend to give themselves credit for wrong answers, especially without a clear model answer to compare against [16].
4. Keep the cards you get right in rotation, at longer gaps.
5. Mix question types: definitions, processes in order, comparisons, and a real case to apply the idea to.

Where the evidence stops

Most experiments use short texts and tests within a few weeks. Benefits shrink without feedback and when the test asks something quite different from the practice. In one classroom study a strong quiz benefit had largely faded three to five months later [17]. Retrieval keeps what you have understood; it does not replace understanding it in the first place.

References

1. 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. doi.org/10.1177/1529100612453266
2. Yang, C., Luo, L., Vadillo, M. A., Yu, R., & Shanks, D. R. (2021). Testing (quizzing) boosts classroom learning: A systematic and meta-analytic review. Psychological Bulletin, 147(4), 399–435. gwern.net/doc/psychology/spaced-repetition/2021-yang.pdf
3. Roediger, H. L., & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249–255. doi.org/10.1111/j.1467-9280.2006.01693.x
4. Karpicke, J. D., & Roediger, H. L. (2008). The critical importance of retrieval for learning. Science, 319(5865), 966–968. doi.org/10.1126/science.1152408
5. Karpicke, J. D., Butler, A. C., & Roediger, H. L. (2009). Metacognitive strategies in student learning: Do students practise retrieval when they study on their own? Memory, 17(4), 471–479. doi.org/10.1080/09658210802647009
6. Kornell, N., & Bjork, R. A. (2008). Optimising self-regulated study: The benefits—and costs—of dropping flashcards. Memory, 16(2), 125–136. doi.org/10.1080/09658210701763899
7. Butler, A. C., & Roediger, H. L. (2008). Feedback enhances the positive effects and reduces the negative effects of multiple-choice testing. Memory & Cognition, 36(3), 604–616. doi.org/10.3758/MC.36.3.604
8. Rawson, K. A., & Dunlosky, J. (2011). Optimizing schedules of retrieval practice for durable and efficient learning: How much is enough? Journal of Experimental Psychology: General, 140(3), 283–302. doi.org/10.1037/a0023956
9. Agarwal, P. K. (2019). Retrieval practice & Bloom’s taxonomy: Do students need fact knowledge before higher order learning? Journal of Educational Psychology, 111(2), 189–209. doi.org/10.1037/edu0000282
10. Pan, S. C., & Rickard, T. C. (2018). Transfer of test-enhanced learning: Meta-analytic review and synthesis. Psychological Bulletin, 144(7), 710–756. doi.org/10.1037/bul0000151
11. Butler, A. C., Black-Maier, A. C., Raley, N. D., & Marsh, E. J. (2017). Retrieving and applying knowledge to different examples promotes transfer of learning. Journal of Experimental Psychology: Applied, 23(4), 433–446. (Abstract.) doi.org/10.1037/xap0000142
12. Hinze, S. R., & Wiley, J. (2011). Testing the limits of testing effects using completion tests. Memory, 19(3), 290–304. doi.org/10.1080/09658211.2011.560121
13. McDaniel, M. A., Agarwal, P. K., Huelser, B. J., McDermott, K. B., & Roediger, H. L. (2011). Test-enhanced learning in a middle school science classroom: The effects of quiz frequency and placement. Journal of Educational Psychology, 103(2), 399–414. doi.org/10.1037/a0021782
14. Karpicke, J. D. (2025). Retrieval-based learning. In Learning and memory: A comprehensive reference (3rd ed., pp. 411–441). Elsevier. learninglab.psych.purdue.edu/downloads/2025/2025_Karpicke_Retrieval_Based_Learning_Review.pdf
15. Mihaylova, M., Zocca, M., Kliegel, M., & Rothen, N. (2025). Does retrieval practice protect memory against stress? A meta-analysis. Swiss Psychology Open, 5(1), 6. swisspsychologyopen.com/articles/10.5334/spo.101
16. Lipko, A. R., Dunlosky, J., Hartwig, M. K., Rawson, K. A., Swan, K., & Cook, D. (2009). Using standards to improve middle school students’ accuracy at evaluating the quality of their recall. Journal of Experimental Psychology: Applied, 15(4), 307–318. pubmed.ncbi.nlm.nih.gov/20025417/
17. Roediger, H. L., Agarwal, P. K., McDaniel, M. A., & McDermott, K. B. (2011). Test-enhanced learning in the classroom: Long-term improvements from quizzing. Journal of Experimental Psychology: Applied, 17(4), 382–395. doi.org/10.1037/a0026252