Because group estimation is superior to individual estimations:
The phenomenon is called wisdom of the crowds. When a group of people independently estimate something, individual errors tend to cancel each other out, leading to a surprisingly accurate collective result. This works because of:
Diversity of opinions: Different perspectives bring a range of estimates.
Independence: Errors aren't systematically biased as long as individuals estimate without external influence.
Error averaging: Overestimation and underestimations balance out when averaged.
Law of large numbers: More participants increase accuracy by minimizing random errors.
It was demonstrated by Francis Galton in 1906, where a crowd's average guess of a bull's weight was almost spot-on. (estimates must be independent and reasonably informed for this to work.)
Diversity of opinions: Different perspectives bring a range of estimates. Independence: Errors aren't systematically biased as long as individuals estimate without external influence. Error averaging: Overestimation and underestimations balance out when averaged. Law of large numbers: More participants increase accuracy by minimizing random errors. It was demonstrated by Francis Galton in 1906, where a crowd's average guess of a bull's weight was almost spot-on. (estimates must be independent and reasonably informed for this to work.)