SwarmQuest

At the West of England Fat Stock and Poultry Exhibition in Plymouth in 1906, people paid sixpence to guess what a fat ox would weigh once it had been slaughtered and dressed. Francis Galton collected the cards afterwards. He set aside 13 that were damaged or unreadable and lined up the other 787 from smallest to biggest.

The middle card said 1,207 pounds. The ox weighed 1,198 pounds: the room's middle guess was less than 1% too high. Galton wrote it up in the journal Nature in 1907, calling it “Vox Populi” — the voice of the people.

In 2014, the economist Kenneth Wallis, rereading the organiser's letter, found a small copying slip in the printed numbers: the ox was probably 1,197 pounds and the middle guess 1,208. Still within 1%.

Galton also promoted ideas about people that were wrong and did real harm. This card is only about his count of the ox guesses.

↔ Stretched — true as usually told; the printed numbers carry a small copying slip. Checked against: Wallis 2014, “Revisiting Francis Galton's forecasting competition” (the 787 cards, the sixpence, both sets of numbers) · Wikipedia: Wisdom of the crowd (the 1906 fair)