The article gives us a few clues: 1. the DK-effect supposedly increases the noisier subjects estimates of their abilities are, 2. the graph relies on breaking

The article gives us a few clues: 1. the DK-effect supposedly increases the noisier subjects estimates of their abilities are, 2. the graph relies on breaking the data into quartiles 3. experts are less noisy in their estimates of their abilities than are non-experts. There is also the paper: https://scholarcommons.usf.edu/cgi/viewcontent.cgi?article=1215&context=numeracy https://scholarcommons.usf.edu/cgi/viewcontent.cgi?article=1... Still I think the article does a disservice in not laying out the argument in plain language. I don't particularly feel like puzzling it out