There's a famous joke along the lines of: Economists have predicted 12 of the 3 market crashes. The problem with looking at who correctly predicted the last c

There's a famous joke along the lines of: Economists have predicted 12 of the 3 market crashes. The problem with looking at who correctly predicted the last crash is that so many people make predictions of the form, "there will be a crash in the next x months". Eventually someone will be correct. How will you be able to tell that person being correct due to random chance versus actually knowing that there would be a crash?