Mistakes are inevitable in the practice of medicine. The most obvious causes are failures in individual performance, such as attention, memory, knowledge, judgment, skill, and motivation. However, they also result, in part, from the nature of medical work, such as the complexity of medical knowledge, the uncertainty of clinical predictions, and the need to make timely treatment decisions in spite of limited or uncertain knowledge. And importantly, mistakes are caused by system factors that influence working conditions. Although much attention has been focused on the effects of errors on patients, it must be understood that medical mistakes are correspondingly distressing for physicians, evoking shock and feelings of remorse, guilt, anger, and fear.
If dealt with effectively, mistakes can provide powerful learning experiences for physicians; however, difficulty in dealing with mistakes may impede both learning and efforts to prevent future errors. Professional norms that assume physician infallibility and treat mistakes as anomalies also pose significant barriers to learning. Judgmental institutional responses and fear of litigation are further disincentives to the open discussion of mistakes. Although some individuals may learn from their own mistakes and make appropriate changes in practice, others are less likely to benefit from these lessons.
It is useful to define a number of terms related to what are commonly referred to as "mistakes" or "errors." The Institute of Medicine (IOM) defines an error as "the failure of a planned action to be completed as intended (i.e., error of execution), or the use of a wrong plan to achieve an aim (i.e., error of planning). An error may be an act of commission or an act of omission." An adverse event is an injury due to health care (IOM, 2000). Errors differ from negligence or malpractice in that an error is not necessarily a proximate cause of harm to a patient. It is also clear that not all judgments that precede bad outcomes are necessarily wrong.
Most studies of medical error have focused on the hospital setting and on adverse events rather than mistakes. Although the overall prevalence of medical mistakes is difficult to ascertain, it appears that they are common. One of the earliest studies examined hospitals in New York State in 1984, and found that injuries occurred in nearly 4% of admissions, with one quarter of these judged to have been due to negligence. A study using the same methodology on hospitals in Colorado and Utah in the 1990s found that adverse events occurred in 3.5% of admissions.
In 2004, the Canadian Adverse Events Study reported on the incidence of adverse events among hospital patients in Canada. The authors randomly selected 4 hospitals (1 teaching, 1 large community, and 2 small community hospitals) in each of 5 Canadian provinces and reviewed a random sample of charts for nonpsychiatric, nonobstetric adult patients hospitalized in each hospital during 2000. Trained reviewers screened all eligible ...