My thanks to Bob Ritholz for the pointer who had a great quote from the scientists:
"Overestimation occurs, in part, because people who are unskilled in these doLmains suffer a dual burden: Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it."
They provided the citation to the original paper:
Psychology, 2009, 1, 30 to 46, www.scirp.org "unskilled and Unaware of It: How Difficilties in recognizing one's incompetence Leads to Inflated Self Assessments" by Justin Kruger and David Dunning. The introduction to the article is a gold mine of citations that support the conclusion that those who do poorly are less likely to realize it.
However, there are apparently other papers that show the effect is less significant, according to one comment on the blog. I have back at home a paper on uncertainty in estimation for estimating the time and effort for software engineering projects. (I am travelling this Summer, probably for about seven weeks.) So I will put these on queue for a future Thoughtful Thursday.)
Obviously, decisions have to be made with the help of expert opinions and whether participatory democracy or not, information on assessing the reliability of such estimates would seem useful to the decision maker. Paul Woodruff gave a wondrous example from Athenian Democracy of interpreting the opinions of generals on the invasion of Syracuse. They also found that people not only could not determine their own ability they were less like to assess competence in others. Can these kinds of social science form a modern piadaia ?