The Testing Effect: Why Quizzing Yourself Can Beat Rereading
The testing effect is the finding that taking a memory test can improve later memory, not just measure it. This article walks through what two experiments did and found, what a meta-analysis and a classroom review add, and where the evidence stops. If you want the how-to instead, read the active recall guide.
A few terms first. Retrieval practice means trying to bring information back from memory. Restudy means reading the material again. A free recall test asks you to write down what you remember, and a meta-analysis pools the results of many earlier studies into one analysis.
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Roediger and Karpicke (2006): tested students remembered more after a delay
Students studied prose passages and then either took recall tests or restudied the passages. Across two experiments, repeated testing led to better recall than repeated restudying when the final test came 2 days or 1 week later (Roediger and Karpicke, 2006).
The result flipped at the shortest delay. When the final test came after 5 minutes, repeated studying produced better recall than repeated testing. The students who restudied also felt more confident that they would remember, even though they remembered less on the delayed tests.
Keep the limits in view. These were two laboratory experiments with prose passages and free-recall tests without feedback. They show that testing helped retention in that setting. They do not promise higher grades, and we read only the abstract.
Karpicke and Blunt (2011): retrieval practice versus concept mapping
A concept map is a diagram of the ideas in a text and how they connect. Making one is a form of elaborative studying, which means working to connect ideas. In this experiment, practicing retrieval of a science text produced greater gains in meaningful learning than studying the text with concept mapping (Karpicke and Blunt, 2011).
The advantage held for questions that tested comprehension and required inferences. It also appeared when the final test asked participants to create concept maps. The authors read the result as support for retrieval-specific mechanisms rather than for elaborative study processes.
Again the limits matter. Participants studied science texts in a controlled study, and results may differ for other subjects or longer courses. Concept mapping done well in class may also behave differently than it did here.
What reviews and meta-analyses add
| Source | What it covered | What it reported | Limit to keep in mind |
|---|---|---|---|
| Rowland, 2014 | A meta-analysis of testing versus restudy. | Initial recall tests gave larger benefits than recognition tests. The results supported a role for effortful processing. | The abstract gives no overall effect size. The author notes that no theory yet explains the effect cohesively. |
| Yang et al., 2021 | A meta-analysis of 222 classroom studies with 48,478 students. | Quizzing raised achievement to a medium extent (g = 0.499). The size varied with the control condition, test format, corrective feedback and number of test repetitions. | An average across many classes, not a guarantee for any person or course. |
| Roediger and Butler, 2011 | A review of retrieval practice research. | Retrieval practice often gave large long-term gains compared with repeated studying. It was often effective without feedback, and feedback enhanced the benefits. | The size of the benefit depends on materials, delays and test formats. |
The symbol g is a standard way to express how big an effect is. The classroom review links the testing effect to three accounts: extra exposure to the material, a match between how you practice and how you are tested (called transfer-appropriate processing), and motivation (Yang et al., 2021). The abstracts we read do not settle which account is right.
What this means for your study sessions, and where it stops
Three practical readings, each tied to a finding above:
- Plan for delay. In the first study above the benefit showed up at 2 days and 1 week, not at 5 minutes. Test yourself well before the exam, not only the night before.
- Make yourself produce answers. Initial recall tests gave larger testing benefits than recognition tests (Rowland, 2014), so write or say the answer instead of picking it from a list.
- Check your answers. Feedback enhanced the benefits in the review by Roediger and Butler (2011). See why you should check every answer.
Now the edges. The studies described here used prose passages, science texts and class quizzes. The abstracts we read do not mention Practice or flashcard apps, and none of them promises higher grades. For methods you can use alone, see how to quiz yourself or try a starter deck on active recall. Why rereading feels effective anyway is covered in the illusion of knowing.
Common mistakes
- Concluding that testing always beats studying. At the 5-minute delay, repeated studying did better than repeated testing (Roediger and Karpicke, 2006). Timing matters.
- Quoting a classroom average as a promise. The medium effect is an average across 222 studies, and it varied with several factors (Yang et al., 2021). Your result can differ.
- Treating these studies as proof that flashcard apps work. The abstracts we read describe passages and class quizzes, not apps. Use them as support for the general idea of retrieval practice.
- Quizzing yourself and never checking the answers. Retrieval practice is often effective without feedback, but feedback enhances the benefits (Roediger and Butler, 2011).
Frequently asked questions
Is the testing effect the same as active recall?
They are closely related. The testing effect is the research finding that taking a test can improve later memory. Active recall is a study method that uses the same idea, where you try to retrieve an answer before you look. Our active recall guide covers the method.
Why did restudying win after 5 minutes?
Roediger and Karpicke (2006) reported that result, but the abstract does not explain why, so we will not guess. The practical reading is that results depend on how long you need to remember. The benefit of testing showed up at 2 days and 1 week.
Does the testing effect work for any subject?
The studies we read covered prose passages, science texts and classroom quizzing. The size of the benefit depends on materials, delays and test formats (Roediger and Butler, 2011), so it may help in many settings, but the amount varies.
Does testing work without feedback?
Often yes. A review reports that retrieval practice is often effective even without feedback, but feedback enhances the benefits (Roediger and Butler, 2011). The first study above used free-recall tests without feedback and still found a delayed advantage.
Sources
We opened each source below before citing it. See Methodology and Sources for how we check them.
- Roediger, H. L., & Karpicke, J. D. (2006). Test-Enhanced Learning: Taking Memory Tests Improves Long-Term Retention. Psychological Science, 17(3), 249-255. Open the source
- Karpicke, J. D., & Blunt, J. R. (2011). Retrieval Practice Produces More Learning than Elaborative Studying with Concept Mapping. Science, 331(6018), 772-775. Open the source
- Rowland, C. A. (2014). The effect of testing versus restudy on retention: A meta-analytic review of the testing effect. Psychological Bulletin, 140(6), 1432-1463. Open the source
- 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. Open the source
- Roediger, H. L., & Butler, A. C. (2011). The critical role of retrieval practice in long-term retention. Trends in Cognitive Sciences, 15(1), 20-27. Open the source
This guide is general study help, not medical or professional advice. It was last reviewed on November 12, 2026. Spot a mistake? Tell us here.