The Leitner system, without the shoebox
The Leitner system is spaced repetition you can run by hand. Cards move between boxes depending on whether you got them right, and each box is reviewed less often than the one before it.
HOW IT WORKS
Every card starts in box 1. Answer a card correctly and it moves up one box. Get it wrong and it goes straight back to box 1, no matter how far it had climbed. Boxes further along are reviewed less often, so your time drifts towards the material you keep missing.
A FIVE-BOX SCHEDULE
- Box 1: every day.
- Box 2: every second day.
- Box 3: twice a week.
- Box 4: once a week.
- Box 5: every two to three weeks.
Keep box 1 small. If it holds more cards than you can answer in one sitting, you are adding new material faster than you are learning the old, and the schedule collapses within a week.
THE RULE THAT MAKES IT WORK
"Correct" has to mean you produced the answer before turning the card over. Recognising the answer once you see it is not a pass. Being strict here is the entire difference between a system that surfaces your weak cards and a box of cards that all quietly end up in box 5.
RUNNING IT DIGITALLY
The paper version breaks down once you have several subjects and a few hundred cards. The same logic works with decks: split a subject into a few quiz decks, review the deck you last scored worst on today, and let the decks you score well on wait a week. Your score history plays the role of the boxes.
Related: spaced repetition explained and the free flashcard maker.
COMMON MISTAKES
- Promoting cards you only half-answered.
- Letting box 1 grow until the daily review is unmanageable.
- Skipping a review day and then restarting the whole box.
- Writing cards long enough that one review takes a minute.
Miss a day and simply carry on where you left off. The schedule is a guide to what to review next, not a streak to protect.