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Tips for Formulating Knowledge

The most common reason flashcards fail isn't the algorithm — it's the cards. A few small habits when writing them will make every future review faster and more memorable. The rules below distill SuperMemo's Twenty rules of formulating knowledge, with a focus on what works for audio.

Keep each card atomic​

One card, one fact. If a card tries to teach two things, you'll grade it on whichever you remember and the other will quietly rot.

Too broad: "Explain cellular respiration, including all stages, key molecules, and every enzyme involved."

Atomic: "What is the main purpose of cellular respiration?"

Split larger topics into a small family of focused cards instead of one giant one.

Make every question unambiguous​

A good question has exactly one right answer. If you can imagine two reasonable replies, the card needs more context.

Ambiguous: "What did Einstein discover?"

Specific: "In what year did Einstein publish the special theory of relativity?"

Include the time, place, or framing the answer depends on.

Don't copy source material verbatim​

Cards lifted straight from a textbook, slide, or article tend to test wording instead of meaning. Read the material, close it, then write the card from memory in your own words. If you can't, you don't understand it yet — and that's the card to make.

Copied: "What is photosynthesis?" → "The process by which plants convert sunlight into chemical energy stored in glucose."

Reformulated: "Why do plants need sunlight to grow?" → "They use it to power the reaction that makes glucose from CO₂ and water."

The second card forces you to use the idea rather than recite a definition.

Write for the ear, not the eye​

This is the part that matters most for audio flashcards. A card that reads fine on screen can fail completely when you only hear it.

  • Keep audio short. Aim for under ten seconds per side. Long sentences exceed working memory when you can't re-read them.
  • Say it out loud before saving. If you stumble reading it, the listener will too.
  • Check text-to-speech pronunciation on acronyms, foreign words, names, and technical terms. When TTS gets it wrong, fix it with SSML instead of rewriting the card.

Recording vs. text-to-speech​

Both work. Pick based on the card:

  • Record your voice when pronunciation, accent, or rhythm is part of what you're learning — language study, song lyrics, lines for a presentation, anything you want to mimic.
  • Use text-to-speech for speed, consistency, batch imports, and topics where the words matter more than how they're said.

You can mix both in the same card.

Avoid common pitfalls​

  • Leading questions. "Isn't the capital of France Paris?" telegraphs the answer.
  • Trivia over insight. Test what you want to use, not what's easy to write.
  • Long lists. Lists are hard to recall as a unit. Split them into smaller cards, or anchor them to a mnemonic. Example: instead of "Name the Great Lakes," ask "What does HOMES stand for?" — Huron, Ontario, Michigan, Erie, Superior.
  • Cards you no longer believe. If your understanding has improved, edit or delete the card. Reviewing a wrong card just reinforces the wrong thing.

Maintain card quality over time​

Treat your library like a garden, not a vault. As your understanding deepens:

  • Edit cards that feel confusing or stale.
  • Delete duplicates and cards you've outgrown.
  • Add follow-up cards when a review surfaces something you almost knew.

When a card needs work mid-session, flag it instead of breaking your flow. Flags mark the card for follow-up so you can keep reviewing now and edit it later from your library.

Next steps​