> For example political polling, data point in time surveys, census, etc. Without verification, what good is the data? Political polls are regularly wrong http

> For example political polling, data point in time surveys, census, etc. Without verification, what good is the data? Political polls are regularly wrong https://www.bbc.co.uk/news/articles/cj4ve004llxo https://www.bbc.co.uk/news/articles/cj4ve004llxo In my country, supporters of one political party seem a lot more likely to tell polling companies they're "undecided" - so the pollsters try to adjust their predictions, based on what they've seen in previous elections. But the problem is getting the adjustment right is very difficult. The political landscape can change a great deal between elections. If John McCain and Donald Trump appeal to very different sets of voters, why should voter behaviour observed with McCain hold true with Trump?