How Priority Ordering Works
Glimpse uses spaced repetition to show you the right cards at the right time, so you spend less time reviewing and remember more.
What priority ordering does
When priority ordering is enabled, Glimpse surfaces the cards you are most likely to forget. Instead of reviewing every card every session, you only see cards that are due for review. Cards you know well are scheduled further apart; cards you are struggling with come back sooner.
This is based on a well-established learning technique called spaced repetition. Research shows it produces 2 to 4 times better long-term retention compared to reviewing everything at once.
The Leitner box system
Every card is assigned to one of five boxes based on your accuracy with that card. Box 1 contains your weakest cards, and box 5 contains the ones you know best.
| Box | Accuracy | Review interval | What it means |
|---|---|---|---|
| 1 | Under 20% | Every session | Needs the most practice |
| 2 | 20 to 40% | Every day | Starting to learn |
| 3 | 40 to 60% | Every 3 days | Becoming familiar |
| 4 | 60 to 80% | Every 7 days | Getting strong |
| 5 | 80% or higher | Every 21 days | Well known |
A card is "due" when the number of days since your last review reaches or exceeds the interval for its box. Cards that have never been reviewed are always due.
To prevent a single correct answer from jumping a card to a long interval, Glimpse requires a minimum number of reviews before a card can reach the higher boxes. A card needs at least 3 reviews to reach box 4 and at least 5 reviews to reach box 5.
How cards move between boxes
Your box placement is based on your overall accuracy with each card, weighted toward your most recent attempts. If your last five answers on a card are mostly correct, that recent streak counts for more than older attempts.
- Answer correctly and your accuracy goes up, moving the card to a higher box with a longer review interval.
- Answer incorrectly and your accuracy drops, moving the card to a lower box so you see it again sooner.
Glimpse weights your recent answers more heavily than your lifetime average. Once you have at least 3 of your last 5 answers recorded, your box is calculated as a blend: 60% from your recent accuracy and 40% from your overall accuracy. This means a sudden slump is caught quickly, but a single bad answer will not completely undo a strong track record.
What happens when you take a break
If you stop reviewing a card, its box gradually drops to reflect the natural forgetting process:
- 7+ days without review: the card drops one box
- 14+ days: drops two boxes
- 30+ days: returns to box 1
This means that when you come back after a break, Glimpse automatically re-prioritizes the cards that are most at risk of being forgotten. You do not need to reset anything manually.
When no cards are due
If you have reviewed all your cards recently enough that none have reached their review interval, the iOS app will show "All caught up" on the practice screen. This is a good thing. It means you are on track and your memory is being consolidated. You can always start a practice session anyway, which will show all your cards sorted by priority.
Availability
Priority ordering is available to Glimpse Pro subscribers on both the iOS app and the web. Free users can practice with shuffle or sequential ordering.
Research behind this approach
The spacing effect is one of the most robust findings in cognitive science. Glimpse's priority ordering is built on decades of research into how memory works and how to make review more efficient.
- Cepeda, N. J., et al. (2006). Spacing Repetitions Over Long Timescales: A Review and a Reconsolidation Explanation . Reviews the evidence that spaced repetition produces 200 to 400% better long-term retention compared to massed practice.
- Wozniak, P. A. & Gorzelanczyk, E. J. (1994). Optimization of repetition spacing in the practice of learning . The foundational SuperMemo research establishing optimal review intervals for long-term retention.
- Settles, B. & Meeder, B. (2016). Enhancing human learning via spaced repetition optimization . Demonstrates that computationally optimized spacing schedules significantly outperform fixed schedules.
- Weinstein, Y., et al. (2022). Evidence of the Spacing Effect and Influences on Perceptions of Learning . Shows that while learners often perceive massed practice as more effective, spaced practice produces superior retention.
- Ye, J. (open-spaced-repetition). ABC of FSRS . Overview of the FSRS algorithm and the research behind modern spaced repetition scheduling, including optimal retention targets and workload balancing.
- Rohrer, D. (2012). Interleaving Helps Students Distinguish among Similar Concepts . Evidence that interleaving different topics during study produces better transfer and long-term retention than blocking by topic.
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