What Is Spaced Repetition?
Spaced repetition is a learning technique where you review material at increasing intervals — just before you would forget it. Instead of cramming everything the night before (which leads to rapid, near-complete forgetting), you space your reviews over days and weeks. The result: genuine long-term retention with significantly less total study time.
The Ebbinghaus Forgetting Curve
In 1885, German psychologist Hermann Ebbinghaus mapped how memory decays over time. Without review, you forget roughly 50% of new information within an hour, and up to 75% within a day. The curve drops steeply at first, then levels off. Spaced repetition exploits this shape by scheduling your next review at exactly the moment your recall starts to slip.
How It Applies to Medical School
Medical education demands holding thousands of simultaneous facts — drug mechanisms, anatomical landmarks, diagnostic criteria, scoring systems. Spaced repetition makes this achievable. Apps like Anki use an algorithm based on SuperMemo (Piotr Wozniak, 1987) to schedule each card. Progress Note's adaptive trivia engine does the same — questions you miss come back sooner, questions you nail get pushed further out.
Optimal Review Intervals
Research suggests the following schedule for new material: first review at 1 day, then 3 days, then 1 week, then 2 weeks, then 1 month. After 5 properly-spaced reviews, most information enters long-term memory. Adaptive algorithms that adjust to your individual performance consistently outperform fixed schedules.
The Clinical Evidence
A 2020 study in Medical Education found medical students using spaced repetition outperformed control groups on shelf exams by 15–20 percentile points — even when they studied fewer total hours. Separate data from USMLE Step 1 takers shows a meaningful correlation between consistent spaced repetition practice and above-average scores.