Smarter forget policy and re-learn tracking

Spaced repetition only works if the system is honest about what you know. The old single-rule response to a "forgot" tap (reset and try again later) covered up an awkward truth: some failures mean "I almost had it" and some mean "I never really had it." Treating them the same lets words drift through the review queue without ever entering long-term memory.

Vocabingo now uses a stage-aware forget policy. Where you forget a word now determines what happens to it.

The three response rules

• Forgot on the day you first learned a word: it stays in the learning queue. A freshly-learned word gets another fair shot in the same window.
• Forgot at the first review the next day: the word is sent back to the learning queue and treated as unlearned. The reasoning is unsentimental. If a word does not survive the first 24-hour gap, it has not been encoded into long-term memory yet, so it re-enters the unlearned pool from scratch.
• Forgot at a later review (one week, two weeks or one month out): demoted one step back to a 24-hour review. Several successful reviews have already laid real traces; one slip earns a recovery shot, not a full reset.

Why the boot-back rule matters

The first 24 hours is the consolidation threshold. A word reviewed before sleep that fails the morning recall test was not stored long-term. The old behaviour quietly recycled it as a "review", which created what users sometimes call ghost progress: cards that have been in the system for weeks but never actually graduated. The boot-back rule kills the ghost. If you cannot recall it the next day, you have not learned it, and it goes back where new words live.

Honest re-learns, honest streaks

A sent-back word reappears in your learning queue. When you learn it again, the system detects the prior history and counts it as a re-learn rather than as brand new vocabulary. The "new words per day" stat stays honest. Re-learns do not double-count.

Streak detection treats either counter as activity. A day where you only re-learn still counts toward your streak. The signal stays positive even when the day was a recovery day.

Measurable, not invisible

Every time the send-back rule fires we record it, which means we can see how often the threshold is doing real work and tune the policy over time instead of guessing. The change is also covered by tests, so the rule is verified and behaves the same way for every learner.

“A good SRS does not flatter you. It tells you what you know and what you do not. The boot-back rule is the algorithm being honest.”

- Vocabingo team