Textbook of Usability

IEC 62366 (Medical devices — Application of usability engineering to medical devices) is the international standard that establishes a regulatory framework for medical device usability. It makes usability a legal requirement for medical devices — including medical software — connecting interface design directly to patient safety.

The standard requires manufacturers to:

1. Establish a use specification — who are the users, what are the tasks, what is the use environment
2. Identify use-related hazards through systematic risk analysis
3. Design the user interface to mitigate those hazards
4. Validate the design through usability testing with representative users
5. Document the entire process as part of the regulatory submission

The standard's emphasis on use-related hazard analysis connects usability directly to patient harm: poor usability is not just a user satisfaction issue but a potential source of injury. A confusing medication ordering screen is not just annoying — it is a hazard that must be identified, mitigated, and tested.

IEC 62366 shifted usability from a nice-to-have quality attribute to a safety requirement with legal implications. Medical device manufacturers selling in the EU, US, or most other regulated markets must demonstrate compliance before their products can be marketed. This has driven significant investment in usability engineering throughout the medical device industry.

The related FDA guidance Applying Human Factors and Usability Engineering to Medical Devices (2016) provides US regulatory perspective aligned with IEC 62366.