--- title: "Quiz, don't re-read: retrieval practice | DuckyHelper" url: "https://duckyhelper.com/research/principles/retrieval-practice/" description: "The testing effect: why pulling an idea out of memory beats re-reading it, with the real numbers from Roediger and Karpicke, and how DuckyHelper quizzes you." updated: "2026-10-09" --- Retrieval practice # Quiz, don't re-read Trying to remember something makes it stick better than reading it again. In Roediger and Karpicke (2006), students who took a practice test recalled 56% of a passage a week later; students who re-read it recalled 42%. Reviews rate practice testing among the most useful study methods. DuckyHelper checks you with quick questions and quizzes, and turns what you miss into flashcards. > “Testing is a powerful means of improving learning, not just assessing it.” [Roediger, H. L., & Karpicke, J. D. (2006). Test-Enhanced Learning: Taking Memory Tests Improves Long-Term Retention. Psychological Science, 17(3), 249-255.](https://doi.org/10.1111/j.1467-9280.2006.01693.x) Figure 1 from Roediger and Karpicke (2006), Psychological Science. Reproduced for commentary. Source: [Roediger, H. L., & Karpicke, J. D. (2006). Test-Enhanced Learning: Taking Memory Tests Improves Long-Term Retention. Psychological Science, 17(3), 249-255.](https://doi.org/10.1111/j.1467-9280.2006.01693.x). In DuckyHelper ## Questions, quizzes and flashcards In the film, Roediger and Karpicke's own chart grows, then a real quiz is answered. Every lesson keeps asking you to pull the idea back out: - A check question after each step (Mac and web) - Quizzes in the moment (Mac and web) - Your turn on the blackboard (Mac and web) - What you miss comes back (Mac and web) ## What the research found Henry Roediger and Jeffrey Karpicke had students read a short passage, then either read it again or take a recall test on it. Five minutes later, re-reading looked better. Two days and one week later, testing won clearly: > The tested group recalled 56% of the material, whereas the restudy group recalled only 42% (Roediger & Karpicke, 2006) Later studies made it sharper. Once students could recall a word, more studying did nothing for a later test, while more testing helped a lot: > Repeated studying after learning had no effect on delayed recall, but repeated testing produced a large positive effect (Karpicke & Roediger, 2008) From Karpicke and Roediger (2008), Science. Reproduced for commentary. Retrieval even beat building concept maps, on a concept-mapping test (Karpicke and Blunt, 2011). A large review of ten study methods concluded: > Practice testing and distributed practice received high utility assessments (Dunlosky et al., 2013) One more finding matters for any tutor: students who re-read often feel surer than they should (Karpicke and Roediger, 2008, found students' predictions were uncorrelated with how they actually did). A quick question is the honest check. ## Feature by feature ### A check question after each step After each step it asks you a quick question and waits for your answer. After it explains a page, it asks one question about what the page says. Every lesson ends with a short recap and one more question. *Mac and web.* ### Quizzes in the moment Say "quiz me on...": multiple choice, true or false, typed math, fill in the blanks, put steps in order, match pairs or label a drawing, with "Not quite" and why when you miss, and a score at the end. In Eddy a quiz docks beside the picture as a Quick check. *Mac and web.* ### Your turn on the blackboard Eddy's blackboard explanations end by handing you a "your turn". *Mac and web.* ### What you miss comes back Missed quiz questions become flashcards by themselves, so you get to retrieve them again later. *Mac and web.* A real quiz answered three ways: a tap, typed math with its live preview, and a key press. What this page does not claim These studies tested other people, other schools and other tools. DuckyHelper has not been tested in a study like these, so none of these results are DuckyHelper's results. They are the reasons behind how it teaches. ## The papers on this page ### Test-Enhanced Learning: Taking Memory Tests Improves Long-Term Retention Roediger & Karpicke, 2006. Psychological Science. Taking recall tests beat restudying for remembering material days later. ### The Critical Importance of Retrieval for Learning Karpicke & Roediger, 2008. Science. Repeated testing, not repeated studying, drove long-term vocabulary recall. ### Retrieval Practice Produces More Learning than Elaborative Studying with Concept Mapping Karpicke & Blunt, 2011. Science. Practicing recall beat concept mapping, even on a concept-mapping test. ### Improving Students’ Learning With Effective Learning Techniques: Promising Directions From Cognitive and Educational Psychology Dunlosky, Rawson, Marsh, Nathan & Willingham, 2013. Psychological Science in the Public Interest. Of ten study techniques, practice testing and spacing were rated most useful. ### The Instructional Effect of Feedback in Test-like Events Bangert-Drowns et al., 1991. Review of Educational Research. A meta-analysis of 58 effect sizes on feedback after test-like questions. ### Principles of Instruction: Research-Based Strategies That All Teachers Should Know Rosenshine, 2012. American Educator. Ten research-based principles, like small steps and checking every student's understanding. ## Frequently asked questions ### What is retrieval practice? Practicing pulling information out of memory, for example with a quiz or a blank page, instead of reading it again. It is also called the testing effect, because taking a test is itself a way to learn. ### Is re-reading notes a good way to study? It feels good but works less well. In Roediger and Karpicke (2006), re-reading won at five minutes but lost at two days and one week, when the tested group recalled 56% against 42%. ### How does DuckyHelper quiz me? Ask "quiz me on" a topic and a short quiz opens while you keep talking. The tutor also asks quick check questions as it teaches, and your missed questions come back later as flashcards. ## Sources 1. [Roediger, H. L., & Karpicke, J. D. (2006). Test-Enhanced Learning: Taking Memory Tests Improves Long-Term Retention. Psychological Science, 17(3), 249-255.](https://doi.org/10.1111/j.1467-9280.2006.01693.x) (accessed 2026-10-09) 2. [Karpicke, J. D., & Roediger, H. L. (2008). The Critical Importance of Retrieval for Learning. Science, 319(5865), 966-968.](https://doi.org/10.1126/science.1152408) (accessed 2026-10-09) 3. [Karpicke, J. D., & Blunt, J. R. (2011). Retrieval Practice Produces More Learning than Elaborative Studying with Concept Mapping. Science, 331(6018), 772-775.](https://doi.org/10.1126/science.1199327) (accessed 2026-10-09) 4. [Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., & Willingham, D. T. (2013). Improving Students’ Learning With Effective Learning Techniques: Promising Directions From Cognitive and Educational Psychology. Psychological Science in the Public Interest, 14(1), 4-58.](https://doi.org/10.1177/1529100612453266) (accessed 2026-10-09) 5. [Bangert-Drowns, R. L., Kulik, C.-L. C., Kulik, J. A., & Morgan, M. (1991). The Instructional Effect of Feedback in Test-like Events. Review of Educational Research, 61(2), 213.](https://doi.org/10.2307/1170535) (accessed 2026-10-09) 6. [Rosenshine, B. (2012). Principles of Instruction: Research-Based Strategies That All Teachers Should Know. American Educator.](https://www.aft.org/sites/default/files/periodicals/Rosenshine.pdf) (accessed 2026-10-09) ## Related principles ### Space it out: spaced practice and forgetting The spacing effect and the forgetting curve: why reviewing after a gap beats cramming, what 317 experiments found, and how DuckyHelper schedules review. ### Explain it back in your own words: self-explanation The self-explanation effect: why students who explain ideas to themselves learn more (Chi et al.), the ICAP framework, and how DuckyHelper asks you to think. ### Feedback right away, on the step What research says about feedback: why it is powerful, why over a third of feedback studies found it hurt, and how DuckyHelper gives feedback on the step. ## Keep reading ### Mix it up: interleaved practice Interleaved practice in plain words: why mixing problem types helps learners tell them apart, what Rohrer and Taylor found, and what DuckyHelper does today. ### The learning-science library: 100+ papers 100+ real learning-science papers behind DuckyHelper, sorted by principle, each with a citation, a link to the publisher and a one-line summary. ### Say quiz me: tap, type math or answer true or false, and every miss comes with why Say quiz me and DuckyHelper writes a quick quiz on what you are learning: tap, type math or answer true or false, and every miss comes with why. ### Hear a word slowly, say it, and see how each word scored; follow along as Eddy reads aloud Practice a language out loud with DuckyHelper: hear a word slowly, say it, and see how each word scored. Have Eddy read a story aloud while the words light up. ## Ready to learn DuckyHelper is ready on your Mac. Learn with Eddy on its blackboard, or with Ducky right on your screen. [Download for Mac](https://duckyhelper.com/download/) [See what it does](https://duckyhelper.com/features/) The Mac app needs Apple silicon and macOS 14 Sonoma or later. There is no Chromebook, Windows or web version right now.