How Encodr's scheduler decides what to show you today
The interval ladder is simple on purpose. Here's exactly how a card climbs it, and why nothing else about the card matters to the schedule.
Open the app on any given day and the cards waiting for you aren't random, and they aren't "everything in the deck." They're a specific, narrow set: whatever is due today, based on one number per card - how long ago you last answered it, and how well.
The ladder
Every card has a position on a fixed interval ladder: 1 day, 2, 5, 7, 10, 14, 21, 30, 45, 60, 90. Answer a card right, and it moves one step up the ladder - the gap until it's due again gets longer. Answer it wrong, and it drops back toward the start. That's the entire mechanism. There's no separate score for confidence, no bonus for how long you've studied the deck overall, no penalty for how many total cards you have. One ladder, one position per card, moved by whether your last answer was right.
Why it doesn't get more complicated than that
It would be easy to add more inputs - how fast you answered, how many total attempts, some blended difficulty score - and some systems do. The trade-off is that every added input is one more thing you have to trust and can't easily audit. A ladder you can describe in one sentence is also a schedule you can reason about: if you keep getting a card right, you know exactly why it's showing up less. If you keep missing one, you know exactly why it keeps coming back tomorrow. That transparency isn't just tidy design - it's what makes the schedule the primary thing to trust over your own sense of "I think I know this," which the research on calibration says is often wrong in a predictable direction.
Why a bigger deck doesn't mean a bigger daily session
Because the ladder spreads cards out unevenly across time, most of a mature deck isn't due on any given day. A 600-card deck you've been reviewing for months has the majority of its cards sitting several weeks out on the ladder; what actually shows up today is new material plus whatever you're currently getting wrong. The deck grows. The daily list mostly doesn't. That's not an accident of the numbers - it's the entire point of scheduling by interval rather than by "review everything, every day."
Encodr turns this into a habit: study anything in a feed, and it schedules the rest.
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