Spaced Repetition
Forget, then retrieve — that’s where the learning happens.
What the Research Says
The brain remembers things better when you review them just as you’re about to forget them. Cram everything the night before and it’s gone within a week. Revisit the same material on day one, day three, day seven, day fourteen and it sticks for months. This is the single biggest difference between students who peak in mocks and students who peak in the real exam.
Evidence Base
| Study | Finding | Impact |
|---|---|---|
| Ebbinghaus (1885) | Without revisiting, 50% of what you learn is lost within an hour and 80% within a day. | The forgetting curve is real — and steeper than most students realise. |
| Cepeda et al. (2006) | Meta-analysis of 254 studies: spaced practice beat massed practice in 259 out of 271 comparisons. | Spacing works across ages, subjects, and skills. |
| Kang (2016) | Optimal gap ≈ 10–20% of the time until the test. For a May exam, that means revisiting material every 3–6 weeks from Year 10. | You can plan exactly when to revisit a topic. |
| Sisti et al. (2007) | Neurons form stronger connections during the “almost forgotten” moment of retrieval. | Struggling to recall IS the learning, not a sign you’ve failed. |
Step-by-Step Method
- 1Learn a topic today — read the lesson, watch the video, write notes. Mark it in a diary or app with today’s date.
- 2Review in 24 hours — do a retrieval practice brain dump, or redo the knowledge check. 5–10 minutes.
- 3Review again in 3 days — if you got it right yesterday, push the gap. Repeat the retrieval.
- 4Review again in 7 days — by now the material is consolidating into long-term memory.
- 5Review again in 2–3 weeks — gap the next review to 14 days, then 30, then 60.
- 6If you fail a review — reset the schedule. Back to day 1. Don’t skip the reset — it’s the point of the system.
The 555 monostable formula T = 1.1RC is easy to see once but fades fast. Re-derive it from scratch at the 1-day, 3-day, 7-day, and 14-day gaps — starting each time from the definition of the RC time constant τ = RC and the threshold voltage ⅔ Vcc. Each re-derivation forces you to reconstruct the reasoning, not just recall a number.
After studying op-amp gain, log the inverting gain formula (A = −Rf/Rin) and the non-inverting gain formula (A = 1 + Rf/Rin) on day one. On day three, cover your notes and apply both to a fresh circuit with Rf = 47 kΩ and Rin = 10 kΩ. On day seven, sketch the output waveform for each configuration given a 0.1 V peak-to-peak sine input and check for clipping.
Common Pitfalls
- Reviewing too often. If it’s easy, the gap is too short. Make it harder by stretching the interval.
- Reviewing too late. If you’ve completely forgotten, you’re essentially re-learning from scratch — you lose the benefit of spacing.
- No written schedule. Spaced repetition works only if you actually do the reviews. Use a calendar, the StudyVault flashcard system, or a simple Leitner box.
- Skipping resets when you fail. If you couldn’t recall the material, you haven’t learnt it — regardless of how far through the schedule you were.
When to Use This
This is the organising principle of your whole revision year — not a technique you pull out near the exam. From the first lesson of Year 10, log every topic you cover and schedule reviews at 1 day, 3 days, 7 days, 14 days, and 30 days. The StudyVault flashcard system does this automatically via the Leitner method — questions move between five boxes with intervals of 1, 2, 4, 7, and 14 days. When a card comes up, do it. When it doesn’t, don’t.