Spaced Repetition — Spaced Repetition Algorithm Tool
A specialized skill that enhances the review-coach agent's review design capabilities.
Target Agent
- review-coach — Review scheduling, weakness reinforcement, long-term memory retention
Ebbinghaus Forgetting Curve-Based Review Intervals
Base Review Intervals (SM-2 Algorithm Variant)
| Review Round |
Interval |
Retention Target |
Action |
| 1st review |
1 day after learning |
80%+ |
Review all items |
| 2nd review |
3 days later |
75%+ |
Focus on items missed in 1st review |
| 3rd review |
7 days later |
70%+ |
Items missed in 2nd review + full sample |
| 4th review |
14 days later |
70%+ |
Weak items + random sample |
| 5th review |
30 days later |
65%+ |
Long-term memory confirmation test |
| 6th+ |
60, 120 days... |
60%+ |
Maintenance review |
Difficulty-Based Interval Adjustment
Dynamically adjust intervals based on learner response quality:
| Response Quality |
Score |
Interval Factor |
Next Interval |
| Perfect recall (instant) |
5 |
x 2.5 |
Significantly extended |
| Correct (slight hesitation) |
4 |
x 2.0 |
Extended |
| Correct (much hesitation) |
3 |
x 1.5 |
Slightly extended |
| Incorrect (recalled after seeing) |
2 |
x 1.0 |
Maintained |
| Incorrect (could not recall) |
1 |
x 0.5 |
Shortened |
| Complete blank |
0 |
Reset |
Start over |
Interval Calculation Formula
next_interval = previous_interval x EF (Ease Factor)
EF update:
EF' = EF + (0.1 - (5-q) x (0.08 + (5-q) x 0.02))
(q = response quality 0-5)
EF minimum: 1.3 (prevents intervals from becoming too short)
Vocabulary Category-Specific Review Strategies
| Category |
Optimal Technique |
Review Frequency |
| High-frequency basic vocabulary |
Repeated exposure in context |
Daily natural exposure |
| Medium-frequency practical vocabulary |
Flashcards + example sentences |
SM-2 algorithm applied |
| Low-frequency specialized vocabulary |
Thematic cluster learning |
Focus during topic study |
| Idiomatic expressions |
Situational role-play |
2-3 times per week |
| Grammar patterns |
Transformation drills + writing |
SM-2 + weekly writing |
Review Session Design Principles
Session Structure (20-minute baseline)
[Start] Warm-up (2 min)
-> Quick recall of 3 key items from previous session
[Core] Spaced Repetition Review (12 min)
-> 20-30 due cards
-> Harder cards first (Interleaving)
[Reinforcement] Weakness Focus (4 min)
-> Re-learn items missed 2+ consecutive times
-> Apply association/etymology/imagery mnemonics
[Wrap-up] Self-Assessment (2 min)
-> Self-rate today's session difficulty
-> Preview next session
Optimal Study Volume
| Learner Level |
New Items/Day |
Review Items/Day |
Total Time |
| Beginner (A1) |
5-8 |
15-25 |
15-20 min |
| Elementary (A2) |
8-12 |
25-40 |
20-30 min |
| Intermediate (B1-B2) |
10-15 |
30-50 |
25-35 min |
| Advanced (C1+) |
5-10 |
20-30 |
20-25 min |
Memory Enhancement Techniques (Applied During Review)
| Technique |
Description |
When to Apply |
| Retrieval practice |
Attempt to recall without hints first |
Every review |
| Elaboration |
Explain why this is the correct answer |
Items answered correctly 2+ times |
| Interleaving |
Mix different item types during review |
Review session ordering |
| Dual coding |
Text + image + audio |
During initial learning |
| Self-reference effect |
Connect to personal experience |
Creating vocabulary example sentences |
