Spaced Repetition: How to Study So You Don't Forget

You've probably crammed all night for an exam, only to find a week later that almost none of it stuck. That's not a failure on your part. Memories naturally fade over time, and if you never bring them back to mind, they disappear fast. Spaced repetition is a study method that turns this tendency to your advantage.

What is spaced repetition?

Spaced repetition means revisiting what you've learned at gradually longer intervals. If you learn something today, you review it tomorrow, then again a few days later, then a week after that, and so on, stretching the gap between reviews a little each time.

The key is to review right before you'd forget. When you work to recall something you've almost forgotten, the memory gets stronger, and it takes longer before you forget it again. That's why the intervals can keep growing the more you review.

Why does it work?

In the 19th century, psychologist Hermann Ebbinghaus measured how much of what he memorized remained over time and summarized it as the forgetting curve. Memory fades fastest right after learning, then declines more slowly as time passes. But a review along the way pushes the curve back up, and afterward it slopes down more gently.

On top of that comes the effect of active recall. Plenty of research shows that covering the answer and trying to recall it yourself makes things stick far longer than rereading your notes. That's why spaced repetition is done with questions or flashcards: you're not rereading, you're retrieving.

How should you space your reviews?

There's no single correct schedule, but a common approach is to start short and roughly double the interval each time you remember. For example:

1. The day after you first learn it (1 day later)
2. 3 days after that
3. 7 days after that
4. Then keep stretching it: 15 days, 30 days, 60 days, and so on

There's one important rule: if you can't recall it during a review, reset the interval to the beginning. If you push something you've forgotten out to a long interval, chances are you won't remember it next time either.

How to do it on your own

1. Turn what you need to learn into questions and answers. Instead of just reading "the definition of a solvent," write the question "What is a solvent?" and put the answer on the back.
2. Ask only one thing per card. If a card asks several things at once, it's easy to count it as correct when you only remembered part of it.
3. When reviewing, try to recall first, then check the answer. If you look at the answer right away, you're left with only the feeling that you know it.
4. Be honest about whether you recalled it or not. That mark decides when you'll review it next.
5. A little every day. Just get through what's due that day. Cramming it all at once breaks the spacing.

How it works in LQuiz

LQuiz does all of the above for you automatically. Create flashcard or multiple-choice questions, add them to a set, and when you study, just tap "Know" or "Don't know."

• Each time you tap "Know," the review interval grows: 1 day → 3 days → 7 days → 15 days → 30 days → 60 days → 3 months → 6 months → 1 year → 2 years → 4 years.
• Tap "Don't know" and it starts over from 1 day.
• You can see at a glance how many questions are due today, and study just those.

No need to write down review dates. Just open LQuiz every day, work through the questions due today, and you're doing spaced repetition.