


Pat is a programmer at a large software company. At best, he’s a middling performer; his code is a mess (initializing variables that are never used, using variable names no one else understands, etc.), he takes longer than he should, and he doesn’t even remember his own code months later.

But Pat’s poor coding skills aren’t his most annoying attribute. What frustrates his manager the most is that Pat is absolutely convinced that he’s a great programmer. Last month was Pat’s performance review, and after receiving a low score from his manager, Pat incredulously argued:

“I’m one of the best programmers in this department! What kind of rating scale are you even using if someone with my talent can get a low score? There’s no way that your performance review form is accurately assessing my abilities. Or maybe you’re just assessing a bunch of stuff that has nothing to do with actually being a programmer!”

If you’ve ever dealt with someone whose performance stinks, and they’re not only clueless that their performance stinks but they’re confident that their performance is good, you likely saw the Dunning-Kruger Effect in action.

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Pat’s programming skills need a lot of improvement. If Pat saw his deficiencies, he would be able to fix them, he wouldn’t fight constructive criticism of his coding, and, frankly, he wouldn’t be so frustrating to deal with.

Unfortunately, we know from the more than 10,000 people who’ve taken the online quiz “How Do You React To Constructive Criticism?” that only 39% of employees handle constructive criticism by systematically dissecting every step leading up to the thing they just got criticized for. They don’t freak out or fight the feedback, instead, they want to understand and correct the underlying issues. Now, it’s not guaranteed that the other 61% are ensconced in Dunning-Kruger, but it’s worth being concerned that they may receive feedback similarly to Pat.

The irony of the Dunning-Kruger Effect is that, Professor Dunning notes, “the knowledge and intelligence that are required to be good at a task are often the same qualities needed to recognize that one is not good at that task—and if one lacks such knowledge and intelligence, one remains ignorant that one is not good at that task.”

The 1999 paper that launched the Dunning-Kruger Effect was called “Unskilled and unaware of it: how difficulties in recognizing one's own incompetence lead to inflated self-assessments.” Across 4 studies, Professor Dunning and his team administered tests of humor, grammar, and logic. And they found that participants scoring in the bottom quartile grossly overestimated their test performance and ability. For example, in one of the studies, Cornell undergrads took a 20-item grammar test. After completing the test, the students estimated how their ability to “identify grammatically correct standard English” compared with others. And as you might expect, the lowest scoring students grossly overestimated their abilities. Those who scored at the 10th percentile (i.e. they scored higher than only 10% of others) rated their grammar abilities at the 67th percentile. In essence, their actual grammar ability was really poor, but they thought they were in the top third of people.

And it’s not just college kids; you can find examples of the Dunning-Kruger Effect everywhere. One study of high-tech firms discovered that 32-42% of software engineers rated their skills as being in the top 5% of their companies. A nationwide survey found that 21% of Americans believe that it’s ‘very likely’ or ‘fairly likely’ that they’ll become millionaires within the next 10 years. Drivers consistently rate themselves above average. Medical technicians overestimate their knowledge in real-world lab procedures. In a classic study of faculty at the University of Nebraska, 68% rated themselves in the top 25% for teaching ability, and more than 90% rated themselves above average (which I’m sure you’ll notice is mathematically impossible).

Now, this isn’t hopeless. I recently spoke with Professor Dunning, who now teaches at the University of Michigan, and he told me that one of the problems in many organizations is that many people are underperforming simply because they don’t know that they could be doing better or what really great performance looks like. It’s not that they’re necessarily being defensive, rather they just lack the knowledge. In fact, he told me that research subjects were willing to criticize their own previous poor skills once they were trained up and could see the difference between their previous poor performance and their new improved performance.


In upcoming articles, I’ll be sharing more of my conversation with Professor Dunning, including how to give people feedback about their performance, given the constraints of the Dunning-Kruger Effect. And I’ll also be sharing how you hire people who are less likely to fall prey to the Dunning-Kruger Effect. But in the meantime, let me share a thought from Confucius that gives us all advice for avoiding, or at least mitigating, this cognitive bias: “Real knowledge is to know the extent of one’s ignorance.”

Mark Murphy is the author of Truth At Work: The Science Of Delivering Tough Messages, Hiring For Attitude and Hundred Percenters.
