The Dunning-Kruger effect, which I have written about several times before, was first published in 1999 by the named psychologists. As the authors have emphasized before – the DK effect is not about stupid people, it is about everybody. However, a recent study calls the basic effect into question – The Dunning-Kruger effect is (mostly) a statistical artefact: Valid approaches to testing the hypothesis with individual differences data. The study essentially showed you can reproduce the DK graph using a randomly generated set of data. Both ends are regressing a bit toward the middle, causing the classic DK graph.