The Dunning-Kruger effect is the idea that incompetent people are the last to realize it. Now we’re realizing that could be wrong.

As a math professor who teaches students to use data to make informed decisions, I am familiar with common mistakes people make when dealing with numbers. The Dunning-Kruger effect is the idea that the least skilled people overestimate their abilities more than anyone else. This sounds convincing on the surface and makes for excellent comedy. But in a recent paper, my colleagues and I suggest that the mathematical approach used to show this effect may be incorrect.

What Dunning and Kruger showed

In the 1990s, David Dunning and Justin Kruger were professors of psychology at Cornell University and wanted to test whether incompetent people were unaware of their incompetence.

To test this, they gave 45 undergraduate students a 20-question logic test and then asked them to rate their own performance in two different ways.