What makes a good trivia question

Rule 1: the answer set must be closed

A question is only worth asking if you can say, without argument, which answers are right and which are not.

“Name a country in Africa” is a good question: the list exists, it is public, and nobody will dispute whether a given country belongs to it. “Name a good film from the nineties” is not: no such list exists, so no ruling is possible.

The rule sounds obvious, yet it is the one broken most often, because opinion questions are the easiest to invent. They give themselves away with one simple sign: if two people acting in good faith can defend opposite answers, throw the question out.

Rule 2: no set defined by a ranking that moves

A question whose answer changes with the news goes stale without warning, and usually without anyone noticing.

“Name one of the ten highest-grossing films of all time” is a trap: that ranking shifts with every big release. A year later the quiz rejects an answer that has become right and accepts one that has become wrong.

Stable sets are the only ones worth building on: the eight planets, the seven colours of the rainbow, the countries bordering another country, the winners of a competition over a closed period. The important word is closed: a period ending on a past date will never move again.

Rule 3: the clue must not contain the answer

This is the most common defect, and the hardest to spot when you are the one who wrote the question.

A clue is written to steer, not to deliver. “From Lenin to Gorbachev” as a clue on Soviet leaders hands over two valid answers at once. The author meant to frame a period; they gave away two points.

The trap is that an example is the most natural way to sharpen an instruction. The fix is mechanical: once the clue is written, reread it looking for a single word that appears in the list of accepted answers. If one does, rewrite it.

Rule 4: one obvious answer, and many more

A good question lets everyone in and still rewards whoever knows more.

That is what makes “name an Olympic sport” more interesting than “which sport joined the Games in 2020”. The first has around thirty right answers, three of which everybody gives. The second has a handful, and you have to know it.

• If only one answer is right, the question is a memory test: you either know it or you do not.
• If thirty are, the question becomes a game: everyone finds something, and the gap opens on what they find.
• The obvious answer has to exist. A question with no way in discourages rather than intrigues.

Rule 5: translating a question is not translating words

As soon as a quiz exists in two languages, the difficulty moves from the wording to the answer set.

A film title often carries two official names with nothing in common. A country is spelled differently. A sport changes name from one country to the next. If the catalogue does not carry both forms, half the players see a correct answer refused with no explanation.

The sound practice is to treat every answer as an object carrying all its forms, rather than a word to translate. A set must point at exactly the same things in both languages, otherwise they are two different questions sharing a title.

These rules, in use

On KRILLION every game serves 7 questions with 25 seconds to answer, and the score depends on how rare the given answer is.

That format turns the five rules above from desirable into mandatory. A fuzzy set becomes unmarkable the moment scoring is automatic. A talkative clue hands out points. And a question that accepts only a handful of answers produces no gap between two players, so no game.