FDA human factors guidance (“Applying Human Factors and Usability Engineering to Medical Devices”) describes the expectations of the US regulatory authority for the human factors process for medical devices. It puts critical tasks, the use-related risk analysis and human factors validation at the center and is decisive for many US approval procedures.
Significance in the US approval process
Unlike an international standard, the FDA human factors guidance is a guidance document of the authority itself. It is not legally binding in the narrower sense and describes the authority's preferred expectations for human factors documentation; alternative approaches are permissible but must be justified from a regulatory perspective. In practice, the FDA nevertheless measures submissions against exactly these expectations. For a growing number of product categories with relevant use risk, human factors documentation is explicitly expected as part of 510(k) or PMA approval procedures.
The general guidance is supplemented by product-specific guidance for individual device categories, which formulates additional expectations tailored to the respective type of product. For manufacturers this means that the general guidance forms the starting point, but product-specific documents must be reviewed in addition.
Core elements of the guidance
- Description of users, use environment and user interface as a coherent system, comparable to the use specification according to IEC 62366-1.
- Identification of critical tasks on the basis of a task analysis and risk analysis.
- Use-related risk analysis: the use-related risk analysis, typically documented in tabular form.
- Formative evaluations for iterative improvement during development.
- Human factors validation: the empirical, summative assessment of the final product with representative users under realistic conditions, with particular attention to critical tasks.
- Documentation: Which human factors information a submission should contain has been described since 2026 by the supplementary guidance “Content of Human Factors Information in Medical Device Marketing Submissions”; see HFE/UE report.
This structure largely follows the same logic as the usability engineering process according to IEC 62366-1, an indication that both sets of rules draw on the same professional foundation even if they use different terms.
Differences from IEC 62366-1
The content proximity between the FDA approach and IEC 62366-1 is great but not complete. In several places the FDA guidance is more concrete and directive than the more principle-based international standard, in particular in the explicit definition and prioritization of critical tasks and in expectations regarding the scope of validation studies.
The handling of results also differs in practice: Use errors observed in validation must be analyzed and assessed explicitly toward the FDA in the HFE/UE report, including a comprehensible justification of why the remaining risk is acceptable. A purely procedural statement that an error occurred does not meet the regulatory expectation.
Expectations for the validation study
For human factors validation, the guidance places particular emphasis on the composition of the participants: Each relevant user group, derived from the user profile, is treated as a group to be examined in its own right, with its own sufficient number of participants. A mixed sample across heterogeneous groups is considered not meaningful enough to make group-specific problems visible.
Equally important is the handling of observed difficulties: Not only complete failures but also laborious, hesitant or detour-based successful task completions are relevant for the assessment. The guidance expects the cause (perception, comprehension or execution) to be clarified for each such case, for example through structured post-task interviews after the task has been completed, deliberately not through classic concurrent think-aloud, because thinking aloud during the task can itself change usage behavior.
Many of the topics addressed by the FDA human factors guidance, known use problems, risk analysis and critical tasks, also support meeting the MDR requirements for ergonomic design and the control of use-related risks according to Annex I.
A joint strategy for both markets
For manufacturers seeking approval in both the EU and the US, a consistently managed process that satisfies both sets of rules is worthwhile. The use specification, task and risk analysis and formative evaluations can generally be used jointly; only the documentation format, terminology and the design of the validation study, in particular the group-wise consideration and the final report, have to be tailored to the respective expectation.
This shared foundation not only saves effort but also increases consistency of content: A product developed and tested according to a uniform logic can be justified coherently toward both authorities, instead of maintaining two parallel, possibly contradictory lines of evidence.
Regulatory reference
The guidance was published by the FDA and is addressed to manufacturers bringing medical devices to the US market via 510(k), PMA or De Novo procedures. It is supplemented by product-specific guidance for individual device categories, which can formulate additional expectations.
The guidance dates from 2016 and was revised in August 2026. In doing so, the FDA aligned the definitions and the section on documentation with the guidance “Content of Human Factors Information in Medical Device Marketing Submissions” (May 2026) and deleted the former Appendix A. The content of the human factors documentation of a submission has since followed this second guidance.
In terms of content, it corresponds to the European usability engineering process according to IEC 62366-1 and is interlinked with risk management according to ISO 14971 via the use-related risk analysis. For other markets, comparable requirements exist with the NMPA usability guidance.
The FDA human factors guidance describes the regulatory expectations for the human factors process for the US market and is closely related in content to IEC 62366-1 but more concretely formulated, especially for critical tasks and the requirements for validation studies.
For manufacturers in both markets, a consistently managed process with a shared foundation is worthwhile; mainly the group-wise consideration, documentation format and the final report need to be adapted.
Frequently asked questions (FAQ)
Is the FDA human factors guidance legally binding?
Not in the narrower sense, because it is a guidance document and not a regulation. In practice, however, it is decisive because the FDA actually measures submissions against these expectations. For products with relevant use risk, corresponding documentation is effectively a prerequisite.
Can a process run according to IEC 62366-1 be used for FDA approval?
Largely yes. The use specification, task and risk analysis and formative evaluations can generally be used jointly. What mainly needs to be adapted are the group-wise consideration in the validation study, the documentation structure and the final HFE/UE report.
What happens if a difficulty but not a complete failure occurs in validation?
That is also relevant for the assessment. The guidance expects the cause of hesitant, laborious or detour-based successful task completions to be clarified (whether a perception, comprehension or execution problem) and this assessment to be documented in the HFE/UE report.
Does a separate study have to be conducted for each user group?
Not necessarily a separate study, but an independent consideration within the validation: Each relevant user group must be represented with its own sufficient number of participants. A mixed sample across heterogeneous groups is considered not meaningful enough.
Do you want to design your human factors process so that it satisfies both the FDA and European requirements? We guide you consistently through both sets of rules.
More about our usability engineeringSources
- IEC 62366-1:2015+AMD1:2020, Medical devices, Part 1: Application of usability engineering to medical devices
- ISO 14971:2019, Medical devices, Application of risk management to medical devices
- Regulation (EU) 2017/745 on medical devices (MDR)
- FDA Guidance: Applying Human Factors and Usability Engineering to Medical Devices
- FDA Guidance: Content of Human Factors Information in Medical Device Marketing Submissions