Errors can be classified into two broad categories, "mistakes" and "slips or lapses". The former occur when something is wrong with the premise on which an action is based. For example, the action in Case A, when the patient was intentionally given a high dose of intramuscular chlorpro-mazine while taking the tricyclic antidepressant dothiepin, represents two mistakes —using the wrong dose in the circumstances, and failing to take account of the presence of a second drug in planning treatment. By contrast, Case E, in which a momentary lapse led to a syringe driver being run at a rate ten times higher than intended, illustrates a slip, which is an error of the second sort, occurring during the execution of a planned action (Reason, 1990). To some extent, training and education will help to overcome mistakes, but it is difficult to prevent slips and lapses by training, because they represent defects in tasks that are not under conscious control.
Was this article helpful?