Which spaced-repetition schedules work best for vocabulary retention
The best spaced-repetition schedules for vocabulary retention generally involve starting with short intervals after initial learning and gradually increasing the gaps between reviews over time. A commonly recommended schedule is:
- Day 0: Initial learning
- Day 1: First repetition within 24 hours
- Day 6-7: Second repetition in about one week
- Day 14-16: Third repetition around two weeks later
- Day 30-35: Fourth repetition around a month later
- Day 60-66: Fifth repetition about two months later
- Day 150: Sixth repetition around five months later
- Day 360: Seventh repetition in about a year
This schedule, inspired by research and popular spaced repetition systems, is effective because it matches the brain’s natural forgetting curve by reviewing vocabulary items just as they are about to be forgotten. After the second repetition, intervals tend to increase by a factor of about 2 to 2.5 to optimize retention with minimal repetition effort.
Research shows that spaced repetition schedules focusing on increasing intervals have only slightly better retention than fixed interval review but are still superior to cramming or no systematic review. The key is that spaced repetition generates an effective cadence for review that helps vocabulary “stick” in long-term memory. Active recall and encoding techniques combined with this schedule further enhance retention.
For language learners, using spaced repetition to review new words more frequently at the start and gradually spacing out repetitions for mastered words is a proven way to build and maintain a large vocabulary efficiently.
In summary, a spaced repetition schedule beginning reviews within 24 hours of learning, then at 1 week, 2 weeks, 1 month, 2 months, 5 months, and 1 year works best to retain vocabulary effectively over time.
This schedule is widely recommended by cognitive research and spaced repetition apps, and it aligns well with the brain’s forgetting curve for optimal language learning retention. 1, 2, 3, 4, 5, 6