Spaced Repetition (SM-2)

SkillPark schedules every card with SM-2, the spaced-repetition algorithm originally developed for SuperMemo in the 1980s and battle-tested since by tools like Anki. It’s simple, transparent, and extremely effective.

The core idea

Review a card at expanding intervals, right before you’d forget it:

• 1st successful review → see it again in 1 day
• 2nd success → 3 days
• After that → the interval multiplies each time (by roughly 1.3×–2.5×, depending on how easy the card has proven for you)

A card you consistently know sails away: 1 day, 3 days, 8 days, 3 weeks, 2 months… SkillPark caps intervals at 180 days, so even your strongest memories get a checkup twice a year.

When you get a card wrong

The card resets to a 1-day interval and starts climbing again. That’s not punishment — a lapse is evidence the memory wasn’t secure, so it needs the short-interval treatment again. The card also becomes slightly “harder” in the algorithm’s eyes, meaning its future intervals grow a little more cautiously.

Why each card has its own schedule

Every card tracks its own easiness factor based on your answer history with it. Easy facts stretch out fast and stop wasting your time; the fact that refuses to stick gets seen often until it behaves. Two students with the same deck end up with completely different schedules — each one personal.

Why this beats cramming

Cramming works for tomorrow’s test and evaporates within the week — that’s the forgetting curve doing its thing. Spaced repetition costs less total time and produces memories measured in months and years. The catch has always been the bookkeeping, which is the part SkillPark automates: you just answer what’s due today.

In classrooms

When a teacher publishes an assignment, each student’s cards enter their own SM-2 schedule. That’s why an assignment spans days rather than one sitting, and why reviews continue even after completion — the schedule is optimizing for retention in March, not the due date.