We saw Galton’s “wisdom of the crowd” before. It says that a crowd’s judgement is more accurate than an individual’s. The near-accurate estimate of the weight of a prize-winning ox by the common public became famous after Galton. But what happens if the mass is wrong?
These are questions on specialised subjects that a knowledgeable minority knows. When such questions are asked, unsurprisingly, the wrong answers get the majority.
Surprisingly popular algorithm
To deal with this problem, researchers from Princeton and MIT have developed a solution that involves two questions instead of one (What do they think the right answer is, and how popular do they think each answer will be?). Take this example.
1) Is Philadelphia the capital of Pennsylvania (Y/N)?
2) What do you think is the prevalent answer (Y/N)?
Philadelphia is not the correct answer (it’s Harrisburg), and only the minority knows that. The majority will say YES to the first; of those, most will respond YES about the others. On the other hand, the minority will answer NO, and since they know it’s specialised information, they also expect most others to say YES. Thus, the ‘YES’ will be more, or the ‘NO’ will be lower in the second case.
Take the difference between the first question and the ‘popular’ question. ‘Yes’ will be negative (first YES < second YES), and ‘NO’ will be positive (first NO > second NO). Therefore, No is surprisingly popular and the correct answer.
Surprisingly Popular: Princeton University
