“How many jelly beans do you think are in this jar?” When subjects were asked this question, guesses ranged from 250 to 4,100; the actual number was 1,116. The average error was 700 — a massive 62% — demonstrating
that the subjects were awful estimators.
Now here comes the weird part. Even with all these wildly incorrect guesses, the average guess was 1,151 — just 3% off the mark.
So although individually, humanity can be woefully inaccurate, collectively, as a group, we have incredible wisdom if our responses are recorded independently and refined.