Reducing Error Through Design

The likelihood of slips, lapses, and mistakes can be reduced through better design. Here are three design guidelines that can reduce the likelihood of errors or minimize their impact should they arise.

Provide Unambiguous and Timely Feedback

The failure to provide clear and timely feedback is one of the most common failings of medical devices (and user interfaces in general). People need clear and often immediate information about the state of a device or the consequences of an action. Without it, they're left to draw their own inferences, sometimes with unfortunate consequences.

Better feedback can, for example, eliminate mode errors. A mode error arises when we perform an action appropriate for one mode, but we are mistakenly in another, as when a nurse assumes (because nothing to the contrary is displayed), that an infusion pump's default analgesic concentration of 1.0 mg has been applied, but the pump was set to 10 mg by a previous user. A safer design would display information about the concentration mode currently programmed into the device.

Unambiguous and timely feedback is also a key to error detection and recovery.

Minimize Distractions

Slips, lapses, and mistakes are all more common when situational factors divert our attention. Situational factors include physiological factors like fatigue, sleep loss, alcohol, drugs & illness and psychological factors such as having to juggle multiple activities, stress, boredom, frustration, fear, anxiety, and anger. But poorly designed user interfaces divert our attention as well.

Device interfaces that provide little or ambiguous feedback, prompt repeatedly with messages and confirmation dialogs, are visually noisy, inconsistent, difficult to navigate, or unnecessarily complex, force our attention toward the device itself, and away from the clinical task at hand.

Well designed interfaces minimize attentional distractions. They permit users to focus attention on their clinical task, not on the the complexities or idiosyncrasies of the device's operation.

Support Error Detection and Recovery

People will make mistakes operating your device. It's inevitable. Helping a user detect when an error has occurred, and helping them recover from it, will make your device safer. An error that is caught before it causes loss, damage, or injury is benign.

Designers can aid error detection by providing clear and timely feedback about the state of the device or the effect of a user's action. Supporting error recovery means making actions reversible (e.g., supporting undo or revert) or stoppable (supporting cancel or override).

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