Why students forget what they learn, and how to plan practice

A student answers a question while the worked example is still on the board, then struggles with it in a later lesson. Those two responses come from different conditions. Before concluding that the lesson failed, check what the student could do independently, what support was available and how much time has passed.

There is no single forgetting percentage or review timetable to apply to every lesson. A useful planning question is: what should each student still be able to recall and use later, and when will I check it?

Try a short retrieval practice routine: recall, feedback, revisit

This proposed starting point assumes students aged 13-16 and one small piece of content that has already been taught: a concept, a short explanation or a procedure. It is a planning assumption, not a tested age range for this routine. Use paper, a pencil and your existing lesson material; no partner class or device is required.

Before the lesson, choose the knowledge you want students to retain. Write two short recall prompts and an answer key naming the essential points and one likely misconception. Prepare a separate new situation in which students could use that knowledge. Check that its language and background information are accessible.

Prepare the prompts and answer key

• Recall prompt 1: "Explain [the taught concept] in your own words. Include [two essential features]." Fill the brackets before sharing the question.
• Recall prompt 2: "Describe the steps in [the taught process], and explain why [one selected step] matters." Choose a prompt that matches what was actually taught.
• Application prompt: "In this new situation, which part of [the taught idea] would you use, and why?" Supply the new situation and decide in advance what a justified answer would include.

Use the prompts as a template, not a requirement to test every kind of knowledge at once. If your lesson taught a short explanation rather than a process, write two questions about that explanation. Keep the answer key focused on meaning; allow different wording that expresses the required idea.

Run the routine across two lessons

Allow about 8-10 minutes for recall and feedback and 5-8 minutes in a later lesson for the revisit and application question. Adjust the prompts and time for your class. A revisit in the following week is one planning option; use students' responses to decide whether another check is needed. These timings and intervals are proposed classroom examples. The studies do not show that these are the best timings.

Keep each student responsible for their own reasoning while retaining their usual accessibility support. An oral response, accessible format or extra time may be appropriate. Record content assistance separately from access support, and do not remove an established adjustment just to make the task look "unaided". If the student cannot begin, offer teaching and support; record that the response was supported.

Use the responses to decide what to teach next

For each essential point, use a simple record such as "present", "partly present" or "not yet shown". Apply the same criteria to the later response and keep application in a separate column. These are proposed classroom recording categories, not a validated scale or a diagnosis.

• If the initial response is incomplete, revisit the teaching or task access before attributing the difficulty to forgetting.
• If the first response is secure but the later response is incomplete, identify the missing idea, give feedback and plan another opportunity to retrieve it.
• If recall is secure but application is weak, examine the new task, its language and the connection the student needs to make.
• If a response improves, record the change without attributing it to this routine alone. Other lessons, feedback, practice and changed question wording may also have contributed.

Decide the next check from the learning goal, the responses and the timetable. Avoid turning a practice check into a public ranking or using a class average to hide individual needs. The aim is to choose a useful next teaching action.

Separate recall, retention and application

• Recall: bringing previously taught information to mind in response to a prompt. Record whether the student used notes, examples or hints.
• Retention: what remains available after a stated delay. A check at the end of a lesson and a check several lessons later answer different questions.
• Application: using knowledge in a new task or situation. Check this separately from repeating a familiar answer.

A correct group presentation tells you something about the finished work. It does not, by itself, tell you what every student can recall independently later. Likewise, an incorrect answer does not establish one cause: check the original learning, the wording of the question and access to the task before deciding what to change.

What two studies can tell us about retrieval and spacing

McDaniel and colleagues studied US eighth-grade science classes in one middle school. In Experiment 1, material quizzed with corrective feedback was compared with material taught but not quizzed. Students performed better on quizzed content in unit and cumulative exams, including an end-of-year exam 5-8 months after the unit exams. There were 139 participants; 92 were included in the main complete-case analysis after attendance and programme exclusions.

The exam questions repeated or closely matched quiz questions. Later unit tests also gave further retrieval opportunities. The study therefore does not isolate retrieval from feedback and extra exposure, or establish transfer to unfamiliar tasks. It did not test peer explanation, project-based learning or Class2Class.

Cepeda and colleagues studied 1,354 adults who completed three online sessions learning 32 trivia facts. They varied the gap before another practice session and the delay before the final test, from 7 to 350 days after that practice. The best gap depended on how much later the final test occurred. The adult factual-learning task and participant attrition limit direct classroom generalisation; this is not a universal school review schedule.

Use these findings to plan recall, feedback and later checks. The routine above is a planning example you can adapt. Neither paper tested this routine, and it has not been evaluated as a Class2Class programme.

Use the same distinction during project work

You can add an individual check around a project discussion or shared product: ask each student to explain one relevant idea before the discussion, then revisit it later. Keep evidence about collaboration and the quality of the shared work alongside, but separate from, evidence of individual retention. Neither cited study establishes that an international project produces lasting recall.

For the separate task of planning what to observe during collaborative work, see our guide to 21st-century skills through global classroom projects. Choose a project for its relevance to your teaching goal, then plan the practice and checks it needs.

Research references

McDaniel, M. A., Agarwal, P. K., Huelser, B. J., McDermott, K. B., and Roediger, H. L., III (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: 10.1037/a0021782. Read the full paper.

Cepeda, N. J., Vul, E., Rohrer, D., Wixted, J. T., and Pashler, H. (2008). Spacing Effects in Learning: A Temporal Ridgeline of Optimal Retention. Psychological Science, 19(11), 1095-1102. DOI: 10.1111/j.1467-9280.2008.02209.x. Read the full paper.