Problems for clinical judgement: introducing cognitive psychology as one more basic science

Overview of errors

Clinical judgement might be flawless under 3 conditions. First, if the demands of medicine fell beneath the intellect of clinicians, clinical judgement would be easier (just as watching television is easy because the complexity of most shows is below the intelligence of most viewers). Second, if practitioners were diligent at checking for errors, serious error would be less likely to occur (just as serious pilot error rarely occurs in commercial flights because of the many error-checking protocols). Third, if the environment offered sufficient safeguards against latent errors, such errors would be diminished (just as children are rarely hurt in daycare because their surroundings compensate for their limitations).

The medical arena tends to violate all these 3 conditions, thereby forming the basis for errors of judgement (Table 1). For example, consider the fact that about 1 of 20 patients presenting to an emergency department with an acute myocardial infarction is mistakenly sent home.5 This error might occur less frequently if chest pain were not so complicated to diagnose, if second opinions were automatic in emergency medicine or if follow-up were infallible. The way to reduce this error is to make the task easier (e.g., with a troponin test), provide more double-checking (such as may occur in a teaching hospital) or install more safeguards (such as CPR training for family members).

Underlying intellectual ability

Individual clinicians may not always recognize that errors in clinical judgement occur in their own practice. The core problem is that people are often poor at judging their own performance. For example, studies show that 85% of people believe that they are better-than-average drivers, contrary to the laws of probability.6 The reason for this misconception is that drivers are often unaware of their mistakes, and occasional lapses are more easily spotted by others. Similar distortions may occur in medicine because of imperfect feedback to clinicians, such as when unsatisfactory care causes patients to complain elsewhere.

The basic reason for worrying about our clinical judgement is that the human brain is a finite organ with bounded capacity. We could all gain by having more memory or intellect, but this is not possible. Although some weaknesses may be offset by technology such as computers, the core exercise of medical decision-making remains fallible because of human limitations and intense time pressures. In addition, the 1.5-kg brain must be directed to more than just clinical judgement: it must juggle simultaneously responsibilities for maintaining balance, modulating personality and all the other usual tasks of daily life. Thus, failures in judgement can confront any physician.7

A distinct fountain of mistakes relates to the mysterious actions of random chance.8 Consider a physician who sees a patient because of a cough, finds no abnormalities, but has a hunch about lung cancer. A series of tests is undertaken, and the physician is eventually proved correct. This experience may lead to an overestimation of the physician's talent, if the initial judgement was more a matter of luck than of skill. More generally, one natural psychological tendency is to assign high praise to personal triumphs with insufficient credit being given to the role of random chance.9

Diligent checking for errors

A related problem involves the tendency for people to form opinions on the basis of early information and, once these opinions are formed, their reluctance to change their opinions even when given important new information. Research in nonmedical settings suggests that experts are particularly prone to persevere with their initial ideas and to change their minds less frequently than would be ideal.10 Changing one's mind is unpleasant because it implies that the original thinking was incorrect. Changing one's mind in medicine is even more troublesome because of the need to explain the switch to patients, families, colleagues and others.

A paradox also arises because clinical judgement is so cherished that it verges on being incorrigible. As an analogy, note that grandparents often consider their own grandchildren to be distinctly attractive, even when no genetic link is present.11 In consequence, the grandparents' adoration makes it hard for them to compare their grandchildren fairly with other children, to hear negative feedback about their grandchildren and to discipline their grandchildren. The same failures may occur when physicians consider their own judgement. This paradox, furthermore, can make articles on clinical judgement seem pretentious or something to be avoided.

A further pitfall is that some errors may remain invisible despite repeated failures and serious introspection. As an analogy, consider the ability to write using proper grammar. The skill needed to construct a sentence that is grammatically correct is the same skill that is needed to check that a sentence is grammatically correct. Likewise in medicine, the wisdom needed to produce good judgement may be the same wisdom that is needed to recognize good judgement.12 Conversely, confidence in one's judgement may merely indicate an unawareness of repeated mistakes. Bad judgement, like bad breath, is often not noticed by its source.

Safeguards in the environment

One further reason for circumspection is that faulty judgement can lead to self-fulfilling prophecies. Imagine a transplantation committee allocating a small number of organs to a large pool of candidates. Competition for selection is intense, so that only patients judged likely to do especially well will receive one of the scarce organs, however, the committee can never really know whether those who were denied transplantation might have done equally well. Moreover, such patients may develop more ominous signs that reinforce the decision, but which might not have occurred had the transplant been granted.

Another vexatious issue relates to the collaborative nature of medical care. Most physicians are highly dependent on the work of others. Thus, clinical judgement can be seriously faulty if based on erroneous charting of vital signs, reports of radiology studies, messages about biopsy specimens or other misinformation. Each of us has the weighty problem of deciding how much time to spend trusting others and how much time to spend personally double-checking. Learning from experience is made even more difficult because of shared guilt and a tendency to blame others when a mistake is discovered.

A final concern is that judgement is a complement to but not a substitute for knowledge. An experienced general surgeon who trusts only his or her judgement and never reads the literature, for example, might be brilliant at diagnosing recurrent ulcer disease but may never realize that it might have often been prevented by antibiotic therapy. Moreover, a physician who does not appreciate the limits of judgement may be unaware of situations when technology offers a superior approach. Even the masterly skills of Sir William Osler could not achieve the results that practitioners obtain routinely today.