The spacing effect: choosing gaps between reviews

A review plan needs two dates: when you return to the material and when you need to use it. A gap that suits a quiz next week may not suit a certification months away.

The gap depends on the goal

Cepeda and colleagues' 2008 experiment found that useful review gaps depended on the final-test delay.

Longer gaps were not always better. This fact-learning experiment does not provide one interval sequence for every subject or learner. It also does not show that every successful review must be followed by a longer gap.

Choose and adjust an interval

1. Note when you need the material and what the task will require.
2. Schedule a return visit that fits the time available, leaving room to correct errors.
3. Attempt a representative question or task and check it against a reliable answer.
4. Record the conditions and result, then decide whether to revisit soon, practise differently or wait longer.

A next-day review followed by one later in the week can be a starting example. It is not a universal prescription. If you cannot complete the task, use an explanation or worked example; do not keep struggling solely to make the exercise harder.

Keep the plan manageable

Use a small set of topics and calendar reminders. Missing a review does not require restarting the whole schedule. Check where you are now and plan the next feasible visit.

Include application practice when the goal is solving problems or performing a procedure. Recalling isolated facts is only one part of that goal. Check generated Piply questions against your material before using the results to adjust your plan.