Polls and opinion surveys often predict results that never happen. Is there a scientific reason that can explain it? I think so. The problem could be that the mathematical theories behind the polls are misapplied.
A branch of statistics is called sample theory. It was invented to solve the problem of estimating whether the products of a factory are well made or defective, without having to analyze them one by one, which would be too costly.
Let us say, for example, that a factory produces one million screws a day. In theory they should be checked one by one, but since that is impossible, only one part is analyzed. Which part? This is what sample theory tries to solve.
Suppose we analyze just 2000 screws, and find that one of them is defective (0.05%). Can we extend this result to the million screws and assert that in that population there will be approximately 500 defective screws?