Spaced Repetition Science

Spaced repetition exploits the spacing effect: information is better retained when review sessions spread over increasing intervals rather than massed together. Each successful recall after a growing delay strengthens the memory trace more than immediate review. Modern systems (Anki, SuperMemo) schedule review at the optimal moment—just before forgetting. The Ebbinghaus forgetting curve shows 70% of new information is lost within 24 hours. With optimally spaced reviews, retention exceeds 90% indefinitely with minimal total review time. Key variables: initial encoding quality, review interval length, and retrieval effort.

When to use it

When you need to permanently retain factual or conceptual knowledge, when preparing for exams or certifications, when learning a new domain where foundations must be automatic, or when evaluating why previous learning didn't produce lasting retention.

How it can help

For knowledge workers needing to retain domain knowledge: implement spaced repetition for anything you want to remember long-term. Practically: (1) create flashcards immediately after learning, (2) use an SRS app scheduling reviews automatically, (3) make cards atomic (one concept each) and personal (your own words), (4) commit to daily review (15-30 minutes). For certifications, languages, or new domains, SRS is the most time-efficient retention method. This also explains why corporate training fails: one-day workshops without spaced follow-up produce near-zero retention.