Had Smith seen the research of David Dunning, a psychology professor at Cornell Universtiy in Ithaca, New York, she wouldn't have had to learn the hard way that there's a subset of people in the workplace who simply can't gauge their own areas of incompetence. Dunning, who originally wanted to learn how people know when they're performing poorly, has found that people who do things spectacularly badly are often as confident in their abilities as highly competent individuals.
In a series of studies, Dunning and his researchers found that people who scored in the bottom 25 percent on humor, grammar and logic tests consistently overestimated their performance and ability. Although these people's test scores tended to put them in the 12th percentile, they saw themselves ranking around the 62nd percentile-even after they were confronted with the entire group's test results.
Because these employees don't see their own incompetence, it's up to you to tell them. But how do you break it to an employee that she's incompetent, especially if it's in her chosen profession?