If you only take one idea from revision science, take this one: spaced repetition. It's the technique with the deepest evidence base, it works for every subject, and it's almost never how children actually revise.
The forgetting curve
In the 1880s, Hermann Ebbinghaus mapped how fast we forget. The shape is brutal: within a day, most newly-learned material is gone — unless you review it. Each review flattens the curve a little more, and each review can happen further apart. After a few well-timed reviews, the knowledge is effectively permanent.
Why cramming feels like it works (but doesn't)
Cramming the night before does raise tomorrow's test score. The problem is what's left two weeks later: almost nothing. Spaced repetition trades a little short-term performance for a lot of long-term retention. For GCSEs and the 11+, where exams test months of material at once, long-term retention is the whole game.
How to actually do it
The rule of thumb: review a new topic the next day, then after three days, then a week, then two weeks, then a month. The moment a review feels easy, push the next one further out. The moment it feels shaky, bring the next one closer.
Doing this by hand is fiddly — which is why almost nobody does it. This is exactly what Clem's mastery engine automates. Every topic your child learns gets a review schedule; when it's due, it surfaces in their daily quest. The child just shows up; the system handles the timing.
It works for reasoning and skills, not just facts
Spaced repetition isn't only for vocabulary or dates. It works for verbal reasoning techniques, Maths methods, Science definitions, English quote banks. Anything you want to be fluent at, space it.
The one catch
Spaced repetition needs honesty — you have to actually try to recall before you check the answer. Re-reading a flashcard isn't retrieval. That's why Clem's practice asks the child to answer first, then reveals the working. The effort of retrieving is where the memory is built.
Start free — Clem's daily quest brings spaced repetition to your child automatically.