I'll be real with you: the first version of CramClub's flashcard system was basic. You'd flip through cards, mark them right or wrong, and that was it. It worked, but it wasn't smart. You'd see cards you already knew perfectly and skip over the ones you were about to forget. That's not studying — that's busywork.
Today I'm shipping the fix. Flashcard review on CramClub now uses spaced repetition — specifically, a system based on the SM-2 algorithm — to schedule reviews based on how well you actually know each card.
How It Works
The idea behind spaced repetition is simple: you should review a piece of information right before you're about to forget it. If you just learned a vocabulary word and you remember it perfectly after 1 day, you don't need to see it again tomorrow. But you should see it again in 3 days. Then a week. Then a month. Each successful recall pushes the next review further out.
If you get a card wrong, the interval resets. The system assumes you need more practice and shows you that card again soon.
Here's what this looks like in CramClub:
- Every card has a mastery level — from New (just added) through Learning, Familiar, Practiced, and Mastered, all the way up to Burned (you know this cold). The level adjusts based on your performance.
- Review sessions are prioritized. When you open a deck, cards due for review appear first. These are the ones the algorithm predicts you're about to forget. You spend your time where it matters most.
- Your ease factor adapts. Some cards are just harder for you than others. The system tracks this per card and adjusts the review schedule accordingly. A card that consistently trips you up gets shown more often than one you always nail.
Why This Matters
Research on spaced repetition is overwhelming. Cepeda et al. found it improves long-term retention by up to 50% compared to massed practice. Karpicke's work in Science showed that retrieval practice (testing yourself) dramatically outperforms rereading or concept mapping.
But here's the thing — most students don't use spaced repetition because it's a pain to manage manually. You'd need to track dozens of intervals across hundreds of cards. Nobody does that. The whole point of building it into CramClub is that you don't have to think about it. Just open your deck, review what the system surfaces, and trust that you're spending your time on the right material.
What's Next
I'm planning to bring this same spaced repetition logic to vocabulary review across our literature guides, language courses, and eventually any content on the platform. The goal is that CramClub always knows what you're about to forget and surfaces it before you do.
Try it out — open any flashcard deck and you'll see the new review flow. Let me know if something feels off. I'm iterating on this fast.
— Peter