Usability according to IEC 62366 refers to the characteristic of a user interface that enables the intended application by the intended users in the intended environment to be carried out effectively, efficiently, and without unacceptable residual risk. The standard IEC 62366-1:2015, supplemented by Amendment Amd 1:2020, establishes a process by which a manufacturer analyzes, specifies, develops, and evaluates the usability of a medical device insofar as it affects safety. The process permits the assessment and control of risks associated with correct use and use errors during normal use; it can identify risks of abnormal use but cannot assess or mitigate them. The second part of the standard series provides explanatory guidance and extends beyond safety considerations.
The Normative Process Flow
The process begins with the use specification, which defines the intended medical purpose, the intended user profile, the intended patient population, the intended use environment, the affected tissue type or body site, and the operating principle. Subsequently, the safety-related characteristics of the user interface and the possible use errors are determined, followed by the known or foreseeable hazards and hazardous situations, with explicit inclusion of experience with similar products.
This is followed by the description of hazard-related use scenarios with tasks, sequence of actions, and severity of harm, as well as their selection for summative evaluation, either in full or based on a justified, severity-oriented selection. Next, the specification of the user interface with testable technical requirements, accompanying documents, and required user training, as well as the evaluation plan for the user interface, are prepared, defining which components are to be evaluated using which formative and summative methods. This is followed by the design of the user interface including accompanying documents and training, the formative evaluations with actual users, typically on prototypes, and finally the summative evaluation, which demonstrates use without unacceptable residual risk.
Integration with Risk Management According to ISO 14971
IEC 62366-1:2015 has significantly strengthened the connection to risk management compared to the previous version and employs the methodology and terminology of ISO 14971. In practical terms, this means: The use errors and hazard-related use scenarios identified in the usability engineering process are inputs to the risk analysis, the evaluation of residual risks is conducted according to the acceptance criteria defined in the risk management plan, and the effectiveness of design-based risk control is verified in the summative evaluation. The results flow back into the risk management file as evidence.
The documentation of the process is maintained in the usability engineering file, defined as a set of records and other documents generated by the usability engineering process. The components may reside in other documents and files, such as development or risk management documentation; conformity is established by review of this file. For European conformity assessment, it should be noted that IEC 62366-1 is not listed in the Official Journal of the European Union and therefore does not trigger a presumption of conformity under Article 8 of Regulation (EU) 2017/745. Nevertheless, it is considered the recognized state of the art; the FDA lists it as a recognized consensus standard.
Distinction from User Experience, Accessibility, and Process Disciplines
The normative concept of usability is narrower than the colloquial understanding of ease of use or user experience. IEC 62366-1 considers usability exclusively from the safety perspective; satisfaction, aesthetics, and efficiency gains are only relevant insofar as they influence use errors. Accessibility must also be distinguished: it is part of the use specification through the user profile but follows its own technical requirements and is not the subject of the standard.
The discipline that implements the standard must be distinguished from the standard itself: The methodological framework, design recommendations, and regulatory expectations are the subject of the entry on Human Factors Engineering for Medical Devices, while the conduct of evaluations with users is addressed in the entry on Usability Studies for Medical Devices. For the distinction between error categories, particularly between use errors in normal use and abnormal use outside the scope of the standard, the entry on Use Errors and Abnormal Use is authoritative.
Relevance for clinical trials
The use specification of the standard and the intended purpose of a clinical investigation must be aligned. If a product is used in an investigation by different user groups or in a different environment than described in the use specification, the application data collected are of limited value for the usability evidence, and conversely, the risk control measures provided for in the process may not be effective.
For study planning, the process provides specific requirements: The hazard-related use scenarios indicate which operating steps must be precisely regulated in the investigation plan, the specification of the user interface identifies the required accompanying documents and training for the investigation sites, and the residual risk assessment determines which operator events must be recorded during the investigation. Full-service CROs such as Mediconomics support manufacturers in aligning the use specification, investigation plan, training materials, and safety reporting, and in feeding application observations from studies back into the usability engineering and risk management files in an auditable manner.
Frequently Asked Questions (FAQ)
What is the scope of application of IEC 62366-1?
It establishes a process for analyzing, specifying, developing, and evaluating usability insofar as it affects safety. Risks associated with correct use and use errors are captured; risks of abnormal use are only identified.
Is IEC 62366-1 a harmonized standard under the Regulation?
No. It is not included in the list of Implementing Decision (EU) 2021/1182 and therefore does not trigger a presumption of conformity under Article 8. The demonstration must be made directly against Annex I of the Regulation.
What belongs in the usability engineering file?
All records and documents generated by the process, including the use specification, analysis of use errors, hazard-related use scenarios, specification of the user interface, evaluation plan, and reports of formative and summative evaluations. The components may reside in other files.
Regulatory References
- IEC 62366-1:2015 including Amd 1:2020 – Process for applying usability engineering to medical devices.
- IEC 62366-2 – Explanatory guidance on the application of usability engineering techniques.
- ISO 14971 – Application of risk management to medical devices, methodological basis for residual risk assessment.
- Regulation (EU) 2017/745, Annex I Chapter I Sections 1 to 5 – Safety, ergonomics, and use errors as the legal reference point.
- Regulation (EU) 2017/745, Article 8 in conjunction with Implementing Decision (EU) 2021/1182 – Presumption of conformity only for listed standards.
