DeepSummary
Francis Galton, a scientist and statistician, conducted an experiment at a country fair about 100 years ago where people guessed the weight of an ox. Contrary to his expectation that the crowd's guess would be flawed, the average of their guesses was almost exactly the weight of the ox, off by just one pound.
This phenomenon, known as the 'wisdom of crowds,' is the idea that a large group's collective answer can be surprisingly accurate, even if many individuals have little knowledge or expertise on the subject. It is the principle behind the stock market, commodity prices, and other aggregated decisions.
To test this concept, the Planet Money team conducted their own experiment, asking over 17,000 people online to guess the weight of a cow named Penelope. Remarkably, the crowd's average guess was within 5% of Penelope's actual weight, even outperforming the guesses of self-proclaimed cow experts.
Key Episodes Takeaways
- The 'wisdom of crowds' phenomenon suggests that the collective answer from a large group can be remarkably accurate, even if most individuals lack expertise.
- Francis Galton's late 19th century experiment at a fair showed the crowd could estimate the weight of an ox with surprising precision.
- Planet Money replicated this by asking thousands to guess the weight of a cow, and the average was within 5% of the true weight.
- This crowd wisdom drives economic forces like the stock market and commodity prices.
- It arises because random guesses cancel out individual errors while pooling collective knowledge.
- However, the effect can break down in cases of cascading group-think or market bubbles.
- Tapping the wisdom of crowds provides a robust model for approximating difficult questions.
- Ironically, even self-proclaimed 'experts' performed slightly worse than the full crowd on guessing the cow's weight.
Top Episodes Quotes
- “So he thought what you were going to end up with was a really flawed guess, because in his mind, what you were doing was you were taking guesses of a few smart people, a few mediocre people, and then a lot of morons because he basically thought everyone was dumb. So he figured the group's guess was going to be way, way off the mark.“ by James Surwicky
- “And the ox, the ox weighed 1198 pounds. So that, in other words, the crowd's judgment was essentially perfect.“ by James Surwicky
- “It's like every person's mind is a different scale for weighing the cow.“ by Jacob Goldstein
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Episode Information
Planet Money
NPR
4/10/24
About one hundred years ago, a scientist and statistician named Francis Galston came upon an opportunity to test how well regular people were at answering a question. He was at a fair where lots of people were guessing the weight of an ox, so he decided to take the average of all their guesses and compare it to the correct answer.
What he found shocked him. The average of their guesses was almost exactly accurate. The crowd was off by just one pound.
This eerie phenomenon—this idea that the crowd is right—drives everything from the stock market to the price of orange juice.
So, we decided to test it for ourselves. We asked Planet Money listeners to guess the weight of a cow.
Spoiler: You can see the results here.
This episode was hosted by David Kestenbaum and Jacob Goldstein. It was produced by Nadia Wilson and edited by Bryant Urstadt. Alex Goldmark is Planet Money's executive producer.
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