According to Wikipedia, the Dunning-Kruger effect is:

...is a cognitive bias in which people with low ability at a task overestimate their ability. It is related to the cognitive bias of illusory superiority and comes from the inability of people to recognize their lack of ability. Without the self-awareness of metacognition, people cannot objectively evaluate their competence or incompetence.

In other words, it's when a person thinks they are much smarter or more capable than they actually are.

Why does it matter in Software Development?

The Dunning-Kruger effect is an important thing for software developers to learn. It can be observed among developers of all ages, though it is more prominent among beginners and intermediate level developers.

After their initial struggle, they may get over confident about a language or their abilities. This leads them to underestimate the complexity of system requirements, or worse, prevents them from coming up with better software/systems designs.

More experienced developers tend to gain wisdom over the years. Though it's not true of all senior developers, they're sometimes better at judging things like system complexity.

The Dunning-Kruger Effect is the exact opposite of Imposter Syndrome. You need to strike the perfect balance between both of these for your professional growth.

How to check if you suffer from the Dunning-Kruger effect?

Though you can never be completely sure if you suffer from the DK effect, you can ask yourself the following questions:

  • Are you able to give accurate estimates?
  • Are you open to learning new concepts?
  • Are you open to implementing or trying new design paradigms?
  • Are you humble?
  • Are you able to take criticism and objectively evaluate feedback?
  • Are you a good listener?