surprising that human decisions and actions are implicated in all organizational accidents. Human beings contribute to the commission of errors in two ways: through the commission of active failures and the creation of latent conditions1 (Reason, 1997).

Active failures occur at the level of the front-line worker (e.g., airplane pilots; control room operators; health care workers, such as nurses, physicians, and pharmacists; and other operators of technology interfacing with people). Such failures are sometimes called the “sharp end” of an error. The types of errors committed by front-line workers involve such phenomena as lapses in memory, misreading or misinterpretation of written data, incorrect performance of a routine activity as a result of a distraction or interruption, or simply human variations in fine motor skills. The consequences of these actions are experienced almost immediately. In the above example, the nurse is the front-line worker at the sharp end of the work process. Her insertion of the catheter using poor processes and tools represents an active failure.

In contrast, latent conditions are factors in the production process or system that are not under the direct control of front-line workers. These factors include poor design of work or equipment, inadequate training, gaps in supervision, insufficient supply of equipment to perform work, undetected manufacturing defects or faulty maintenance, inadequate personnel deployment, and poorly structured operations. They arise from strategic and other top-level decisions made by entities at the “blunt end” of an organization or production system, such as government regulators, manufacturers, system designers, and high-level managers and decision makers.

The error described above resulted from multiple latent conditions. First, the new nurse had not had practical experience in either her nursing school or her workplace in the performance of this specific task. A mechanism for identifying the presence or absence of core nursing skill competencies would have detected this lack of experience, so that the nurse could have received instruction to fill this gap in her skill set. Further, the mechanism used to deploy staff created a situation in which all the nurses on duty in the unit at the time of the event were similarly new and inexperienced. Thus the nurse committing the error had no source of clinical expertise to whom she could turn for advice. Necessary supplies also were not available; the nurse was forced to improvise using equipment not specifically designed for the procedure, thereby creating opportunities for faulty technique. It is important to note, moreover, that the nurse did not give evidence of feeling


To Err Is Human employs the terminology “active and latent errors” used in Reason’s 1990 publication, Human Error. Reason’s subsequent (1997) publication, Managing the Risks of Organizational Accidents, refines that terminology and now refers to active “failures” and latent “conditions.” We adopt this more recent terminology here.

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