Spaced repetition for Bible memory: what it is and why it works

In 1885 a German psychologist named Hermann Ebbinghaus memorized thousands of nonsense syllables, tested himself at intervals, and drew the curve that every memory app is still built on. It showed two things: memory fades fast unless it is used, and each successful recall makes the next fade slower.

The practical implication took another century to turn into software. If you review something right before you would have forgotten it, you get the maximum strengthening for the minimum effort. Review too early and it was wasted. Review too late and you are relearning from scratch.

The algorithm, in plain terms

Spaced repetition systems give every item, in our case every verse, its own schedule. When you review and grade yourself, the system adjusts:

• Got it easily? The next review is pushed out further. One day becomes three, three becomes a week, a week becomes a month.
• Struggled? The interval shrinks, and the verse's ease drops a little so it will be shown more often in future.
• Forgot? Back to the start. The verse is treated as new again.

Versed uses a variant of the SM-2 algorithm, the same family behind Anki and SuperMemo. What is different is the material.

Why verses are not vocabulary

Flashcard apps were designed for pairs: a word and its meaning. A verse is a sequence of thirty words that has to come out in order. That changes a few things.

Grading has to be about words, not gist. Versed's typed-recall modes compare what you typed against the verse word by word, forgive typos, and show you exactly which words you dropped. "Close enough" is a real grade, and so is "word-perfect."

The mode should change as the verse matures. A brand-new verse is reviewed in Read & Recognize: see it, say it, grade yourself. As it stabilizes, Versed switches to Fill in the Blanks, then First Letter Hints, then recall from the reference alone, then reverse recall (verse shown, you name the reference). A verse that has been retrieved from every direction is a verse you own.

Backlogs must be survivable. Miss a week and a naive scheduler dumps sixty due cards on you. Versed caps a backlog session, prefers verses already in progress over brand-new ones, and says so on the home screen: "Let's start with twenty; the rest can wait."

What the ladder looks like

| Stage | What you see | What you do | |---|---|---| | New | The whole verse | Read, reveal, grade | | Learning | Verse with blanks | Recall the missing words | | Young | First letters only | Type it back | | Mature | Just the reference | Type the verse from nothing | | Mastered | Verse, no reference | Name where it lives |

Verses that stay mastered long enough are retired as written and drop out of review entirely. They are yours.

The honest-grading problem

Spaced repetition only works if you grade yourself truthfully. The temptation, when you fumbled two words, is to tap "Got it" anyway. Do that and the algorithm believes you, waits a month, and the verse is gone.

Versed makes the honest choice the easy one: the typed modes grade themselves, and the self-graded modes show the projected interval under each button, so you can see what "Easy" actually commits you to.

The habit is the algorithm

None of this works without showing up. The scheduler can only schedule; you have to open the app. That is why the daily session is short by design, why reminders are one per day at a time you choose, and why a streak comes with grace days. The math is simple. The habit is the hard part, and the whole product is built to make it a little easier.