Why not use the crowd?
Scoring against other players has two weaknesses. On day one nobody has played, so there is nothing to compare with, and early scores would be arbitrary. And once a few people share a clever answer, it stops being rare and your score changes depending on when you played. We wanted a prompt to be worth the same to everyone, on any day, at any hour, and we wanted to be able to explain the number.
The two ingredients
Obviousness is our estimate of how likely a person is to say an answer first for that particular prompt. Apple is extremely obvious for “Name a fruit”; medlar is not. This carries about three quarters of the score. Word rarity uses the open-source wordfreq project to see how often a word appears in everyday writing, and contributes the other quarter. For names of people, places and brands, and for prompts about situations, word rarity says little, so it is switched off and the score rests on obviousness alone.
The two are blended and then curved, so the top of the scale is hard to reach. A pretty good answer lands in the middle; only genuinely uncommon ones reach the 90s.
Three worked examples
- “Name a fruit”: apple. The most obvious answer there is, so it scores about 2 out of 100.
- “Name a fruit”: lychee. Many people know it but few say it first. It scores in the middle of the range.
- “Name a fruit”: ugli fruit. This is the prompt’s summit: real, correct and almost never said, worth exactly 100.
Only the summit can reach 100. Every other answer is capped at 90, so finding all seven summits in a day (a perfect 700) is a real feat.
What the method gets wrong
These are estimates, and they will sometimes be wrong. A word may look rare in writing but be familiar to a whole region. An answer we rated as middling may be the first thing half the world says. Because ratings are fixed in advance we can correct them whenever a mistake is spotted, and every prompt keeps a review sheet of its top answers for exactly that reason. If a score looks off to you, send it to us with the prompt and answer.
The full table of bands and verdicts is on the scoring page.