How Can We Eliminate Error When We Have No Consistency?

Abstract

Consistency is one of the most universally articulated usability principles for user interface (UI) design. Everyone who works in this field harps on about the importance of consistency of navigational style, terms used, screen layout, instruction format, illustrative style, text layout, and consistency of control mechanism, to name a few categories typically mentioned.Thus, to the extent that the software developers, engineers, and designers with whom we collaborate listen to us human factors professionals (and they increasingly do), UIs in the healthcare arena are becoming quite consistent. Newer electronic medical record (EMR) systems and medical device UIs are very consistent. You will also find a lot of consistency among the dozens of screens of the most recent programs that articulate with implanted defibrillators, the UIs of the latest ultrasound systems, large-volume infusion pumps (LVPs), patient-controlled analgesia pumps (PCAs), in vitro diagnostic systems, etc.The problem is that this consistency does not extend beyond individual systems (really subsystems) or devices—we've achieved intra- but not inter-system consistency. At any hospital, for example, you will find a pretty decent UI with the EMR system for running the pharmacy and a pretty decent UI with the system for running the surgical suite. However, the two will be completely different, and will also be different from the hospital-wide systems used to order supplies, keep track of outpatients, and track emergency room admissions.Some of the associated system UIs have been developed in-house by information technology (IT) departments, others by outside contractors, and yet others are off-the-shelf products. Inevitably, healthcare professionals who use these systems have to keep track of the fact that, for example, selections are made with check-off boxes in one system, while equivalent selections are made with pull-down menus in another.Users have to learn color-coding conventions and symbol sets that often contradict each other. They have to remember that what one system calls “format,” another calls “layout,” and so on. A nurse learns a set of alarm conventions with one infusion pump, and another set for a different pump. The two pumps may be used with the same patient (such as an LVP and a PCA), or the hospital may have a new contract with a different manufacturer, which means that all the old pumps are of one type, and the new ones are of another. Staff on the hospital floors may use one pump and those in the surgical suites another.In other words, what we're dealing with is the Wild West. Is it any wonder, then, that there is an ongoing epidemic of use errors? We can blame “error-prone” healthcare professionals as much as we like, but as long as we subject them to this between-device and between-system inconsistency, errors will occur.Indeed, the emphasis the U.S. Food and Drug Administration (FDA) has placed on reducing device use errors recently, is without a doubt, resulting in safer devices. But it is not really addressing the between-device inconsistency that challenges healthcare professionals, let alone patients, as devices and systems increasingly move out of the hospital and into the home.The ultimate problem is that there is no mechanism for achieving system-wide consistency for users. There is only a mechanism in place to achieve consistency of specific devices and subsystems, since that is where the decisions are made and regulations apply. Until that changes, patients and healthcare professionals are going to have to cope with the Wild West.