One alternative would be an opinion poll. The drawback is that many “opinions” are invented on the spot to satisfy a pollster. Political scientist George Bishop once demonstrated this by asking people whether they favoured repeal of the “Public Affairs Act of 1975.” There was no such act. But thirty percent took the bait and offered an opinion. Bishop found that the less educated were more likely to claim an opinion.
Excerpt from: Head in the Cloud by William Poundstone