As a chief of staff, I was the head disciplinary officer of the two hospitals where I served in that office. I found it nearly impossible to rein in a persistently erring doctor. The emphasis is on the word "persistently" because the other kind of doctor makes a mistake that comes to the attention of a medical staff committee once in a blue moon.
A targeted doctor who made multiple recurrent errors would fight a rear-guard battle that went on for years to keep his or her practice and income. He or she would not improve their care of patients during those periods despite letters from quality assurance (peer review) committees criticizing their care of patients. Sometimes they would ignore letters of inquiry from the peer review committees altogether. Face to face conferences of the committees with repeatedly blundering colleagues dealing with how their care differed widely from established norms availed little. They were clearly different from their colleagues, who made occasional and sometimes serious mistakes. In response to the obligatory letters from the committees, the latter would often write contrite letters acknowledging their errors. When they did write back, the recurrently mistaken doctors would not admit to the committees that they had made errors. The difference between them and their repentant colleagues was a lack of insight into their own limitations.
Most striking to me was that on the occasions I had to confront them personally, I often got the impression that they were not engaging in a cover up. They had never admitted to themselves that they had made mistakes. Even when confronted with irrefutable CT scan evidence of his having operated on the wrong side of a patient's body, one insisted that he had operated on the correct side. Another, when confronted with images of an incompletely obliterated brain aneurysm, half of it still filling with dye on follow up x-rays, insisted that he had gotten the whole lesion.
In the late nineties, Dunning and Kruger, academic cognitive psychologists, studied what appears to me to be a similar phenomenon. They used college students as their subjects. They found that low performers on routine class examinations overrated their own performance by a considerable degree. Those in the middle were accurate and those at the very top tended to underestimate their abilities by a small amount. The group at the low end were characterized by the authors as "doubly cursed"; they not only performed poorly but were unaware of their flaws. When similar observations were done by Hodges, Regehr and Martin on family practice residents --young physicians in training-- testing their ability to obtain a medical history from a patient, similar results were obtained. The residents in the lowest one-third of the group had no idea how badly they had done.
The Freudians might have said that denial and/or rationalization, two classical so-called defense mechanisms were at play. Dunning and Kruger simply said that the same cognitive deficits that caused people to perform poorly made them unable to perceive their own errors. These deficits could only partly be corrected by additional education.
The authors of the paper on family practice residents, Hodges, Regehr and Martin, warn that their observations cannot be extended to other specialists or skills. However, for me, the similarities between their scientific observations and what I observed in real life appeared great enough for me to comment upon them. I believe that it is manifestly true that a lack of perception of one's own flaws is a great obstacle to improvement and in medicine is a grave danger to the well being of patients.