Spaced Repetition System
Optimize review timing to maximize long-term retention with minimal effort
The Forgetting Curve Problem
Hermann Ebbinghaus discovered that we forget ~50% of new information within 24 hours, ~70% within a week, and ~90% within a month—unless we review. But reviewing everything daily is inefficient. Spaced repetition schedules reviews at optimal intervals to combat forgetting with minimal time investment.
Key principle: Review just before you're about to forget. Each successful recall strengthens memory and extends the next review interval.
The Optimal Review Schedule
Based on Ebbinghaus + modern research (Pimsleur, Leitner, SuperMemo algorithms):
Review Schedule Calculator
Calculate Your Review Dates
Implementation Strategies
Strategy 1: Manual Calendar System
- • After learning new content, create calendar reminders for review dates
- • Label: "Review [Topic] - Spaced Rep #1" etc.
- • Spend 10-15 min per review (active recall, not re-reading)
Strategy 2: Flashcard Apps (Anki, Quizlet)
- • Apps automatically schedule based on your recall success
- • Anki: Most powerful, steep learning curve
- • Quizlet: Easier interface, less customization
- • Review daily (10-20 min)—app shows only what's "due"
Strategy 3: Physical Leitner Box
- • 5 boxes: Box 1 (daily), Box 2 (every 3 days), Box 3 (weekly), Box 4 (biweekly), Box 5 (monthly)
- • Correct recall → move card to next box. Incorrect → back to Box 1
- • Simple, tactile, no screen time
Subject-Specific Adjustments
Languages & Vocabulary
Use shorter intervals initially: Day 1, 2, 4, 7, 14, 30 (vocabulary decays faster)
Conceptual Subjects (Physics, Economics)
Combine with problem-solving: Don't just review notes, work practice problems at each interval
Essay Subjects (History, English)
Review key arguments + examples: Practice writing thesis statements at each interval
Key Takeaways
- Review at expanding intervals: 1, 3, 7, 14, 30, 60 days
- Active recall during review (test yourself, don't re-read)
- 10-15 min daily review more effective than cramming
- Use Anki or similar apps for automated scheduling
- Start spaced repetition immediately after learning, not before exams
Key Research References
- • Ebbinghaus, H. (1885). Memory: A Contribution to Experimental Psychology.
- • Cepeda, N. J., et al. (2006). Distributed practice in verbal recall tasks. Psychological Bulletin, 132(3).
- • Karpicke, J. D., & Roediger, H. L. (2008). The critical importance of retrieval for learning. Science, 319(5865).
