Human Factors Engineering (HFE) is the discipline of applying knowledge about human abilities, limitations, and behavior to medical device design so the device can be used safely and effectively by its intended users. In medtech, it identifies, reduces, and verifies use-related risks across the user interface, following IEC 62366-1.
What is Human Factors Engineering (HFE)?
Human Factors Engineering (HFE), also called usability engineering, studies how people interact with a device and uses that knowledge to shape its user interface. The interface includes everything a user sees, touches or hears: displays, alarms, controls, packaging, labelling and instructions for use.
HFE belongs within medical device design and development and operates alongside risk management rather than functioning as a final compliance check. Its practical goal is to identify and prevent use errors that could harm a patient, operator or caregiver.
Why Human Factors Engineering (HFE) matters in medical device development
Use errors cause a large share of device-related adverse events. A pump programmed in the wrong units or an ambiguous alarm can injure a patient even when the hardware works perfectly. Regulators treat usability as a safety issue, not a convenience feature.
The FDA reviews use-related risk analysis and usability-validation evidence within premarket submissions, while EU MDR Annex I requires manufacturers to reduce risks associated with ergonomic features and reasonably foreseeable use error. Weak HFE evidence can delay regulatory review and market entry. Strong, traceable evidence reduces review questions and lowers post-market exposure.
How Human Factors Engineering (HFE) works
HFE follows a defined process under IEC 62366-1:2015/AMD1:2020, the international standard for applying usability engineering to medical devices. The process feeds directly into risk management under ISO 14971:2019. The typical steps are:
- Use specification. Define the device’s intended users, intended use and use environments, including relevant user capabilities, limitations, training and operating conditions.
- Hazard-related use scenario analysis. Identify tasks where a user error could cause harm, and flag critical tasks.
- User interface design and evaluation. Develop the interface and test it through formative studies during development.
- Summative usability validation. Test the final or near-final interface with representative users under realistic conditions to confirm that critical tasks can be performed safely and that implemented use-related risk controls are effective.
- Documentation. Record results in a usability engineering file that supports the design history file.
In the United States, the FDA guidance “Applying Human Factors and Usability Engineering to Medical Devices” (2016) sets expectations, and the now-final “Content of Human Factors Information in Medical Device Marketing Submissions” (2026) defines risk-based submission categories that determine how much HFE evidence a 510(k), De Novo, or PMA must carry. Design controls under 21 CFR Part 820 and ISO 13485 require usability to be part of design validation. For medical electrical equipment, IEC 60601-1-6 points back to the same 62366-1 process. AAMI HE75 offers detailed design guidance.
Common challenges and best practices
The frequent mistake is treating HFE as a documentation exercise near design freeze. By then, the interface is fixed, and validation becomes a box to tick rather than a real test. Teams also run summative studies with the wrong participants or define critical tasks too narrowly, so a failed task surfaces only after launch.
Good practice starts early and stays iterative:
- Run formative testing on rough prototypes, then refine before summative validation.
- Tie every hazard-related use scenario back to the ISO 14971 risk file so nothing is orphaned.
- Recruit participants who match the real user profile, including lay users for home-use devices.
- Treat instructions for use and training as part of the interface, not a patch for poor design.
- Confirm your submission category early so you collect the right evidence the first time.
How SJML helps with Human Factors Engineering (HFE)
SJML builds usability engineering into device design rather than adding it at the end. Its engineering teams run user-needs analysis, develop and test user interfaces, and align usability work with IEC 62366-1 and risk management under ISO 14971, as part of an electromechanical design path that spans mechanical, electronics, embedded, and software engineering. The QARA group supports the regulatory side: design history files, usability documentation, and submission strategy for FDA, EU MDR, and other markets. This pairing keeps HFE evidence consistent from early concept through design transfer.
Frequently asked questions
Yes. In medical devices, the two terms are used interchangeably. IEC 62366-1 titles the discipline “usability engineering,” while the FDA tends to say “human factors engineering.” Both describe the same goal: designing the user interface so that intended users can operate the device safely, and confirming that use errors which could cause harm have been reduced as far as possible.
IEC 62366-1:2015/AMD1:2020 is the core international standard. It defines the usability engineering process and links it to risk management under ISO 14971:2019. The supporting technical report IEC/TR 62366-2:2016 adds guidance and methods. In the United States, FDA human factors guidance documents set submission expectations that complement, rather than replace, IEC 62366-1.
Formative testing happens during development. It is exploratory, uses early prototypes, and feeds findings back into design. Summative testing, also called usability validation, comes at the end. It uses the final or near-final design, representative users, and realistic conditions to confirm that critical tasks can be performed safely. Regulators rely on summative results as validation evidence.
No. The level of human factors information depends on use-related risk. The FDA’s “Content of Human Factors Information in Medical Device Marketing Submissions” guidance sets risk-based categories that decide how much evidence a submission needs. Devices with critical tasks, novel interfaces, or known use problems generally require summative validation; lower-risk modifications may need only a justification.
