Editor's note: This guest editorial originally ran in the May 1995 issue of MD+DI. After publishing a recent article on identifying the root cause of use errors, we received a note from William Hyman, author of this article, alerting us to the fact that the term "use error" was originally coined in his 1995 piece for MD+DI.
The way in which users interact with medical devices, and incidents related to such interaction, have received considerable attention in these pages1–3 and elsewhere.4–6 Usability, and the consequences of poor usability, are important in device design and testing, prepurchase evaluation, and malpractice and product liability litigation. Usability and human factors issues have also been the focus of a variety of FDA efforts including safety alerts, encouragement of certain recalls, and, perhaps increasingly, in the process of device clearance and approval.3 In all of these areas of interest the fundamental usability issue is understanding those aspects of the design, marketing, and clinical implementation of a device that make a device that is technically capable of achieving the intended performance into one that can actually and consistently achieve that performance under the real conditions of use by real users.
When correct device use does not occur, the simplest, and most common, explanation is "user error." This term implies the incorporation of two conclusions: first, that the direct cause of the problem was the user, and second, that the user was therefore at fault. This dual implication is unfortunate because it masks the many ways in which the design of a device, personnel issues, and working conditions can contribute to problems in using a device safely and effectively. Thus the conclusion "user error" can detract from the perception of the need to improve a design or other aspect of the overall device-use scenario.
A preferred term to user error is use error, which describes the immediately precipitating clinical event; that is, there was a problem associated with the use of the device. "Use error" avoids the immediate assignment of cause by providing an identification only of what happened, not why. Thus the occurrence of an incident in which there was a problem with the use of a device would be first identified as a use error. This would then lead to further study to determine why the use error occurred. The conclusion of this further study might them be lack of adequate training, poor human factors design, inadequate stafing, or some combination of these and other considerations.
Another clarification that has been suggested is to distinguish users from operators.4 According to this distinction, the individual with his or her hands on the device is the operator, while others in the chain of responsibility and control of the device are users. Thus the hospital as an entity is a device user, while the nurse, physician, or other health professional actually working the device is an operator. When we make this distinction, "operational error" replaces operator error as the first-level conclusion in the same way that "use error" replaces "user error."
The distinctions proposed here are intended to be mroe than just semantic ones. The identification and understanding of the cause or causes of errors during the use of medical equipment is critical to the prevention of recurrence, the management of incident-related risks, and regulatory matters such as medical device reporting and safety alerts. Clear terminology can help to distinguish the immediate cause of an untoward event from the underlying factors that gave rise to that cause and thus help to clarify subsequent assignment to blame.
1. Doriot C, "Design for Usability," MD+DI, 11(3):8, 1989.
2. Wiklund ME, "Human Error Signals Opportunity for Design Improvement," MD+DI, 14(2):57–61, 1992.
3. Sawyer D, and Lowery A, "CDRH's Role Promoting User-Oriented Design," MD+DI, 16(3):72–82, 1994.
4. Sheperd M, and Brown R, "Utilizing a Systems Approach to Categorize Device-Related Failures and Define User and Operator Errors," Biomedical Instrumentation & Technology, 26(6):461–475, 1992.
5. Bogner S, "Medical Devices: A New Frontier for Human Factors," CSERIAC Gateway 4(1):12–14, 1993.
6. Bogner MS (ed), Human Error in Medicine, New Jersey, Lawrence Erlbaum Associates, 1994.
William A. Hyman is professor emeritus and the former chair of the biomedical engineering program and interim department head of biomedical engineering at Texas A&M University. His research focuses on system safety in medical device design and clinical engineering. Dr. Hyman has written over 80 publications and is coauthor on 10 books. He serves as editor of the Journal of Clinical Engineering and has taught numerous short courses. He received his doctorate of science and masters degree in engineering mechanics from Columbia University.