Massed vs distributed
Massed practice studies everything at once: a single long session before the test. Distributed practice splits the same time across days or weeks. Cramming can work for an exam tomorrow, but the memory fades fast afterward.
A large meta-analysis of the spacing effect (Cepeda and colleagues — see our sources page) found that distributing practice reliably improves retention compared with massing the same amount of study.
Why it works
When you return to material after a gap, it has partly faded, so retrieving it takes effort — and that effortful retrieval is what builds durable memory. Each spaced session also catches the forgetting curve before it bottoms out and resets it higher.
Distributed practice and spaced repetition are closely related: spaced repetition is a precise way to distribute practice, timing each return for maximum benefit.
