August 19, 2026
Written by Eric Jacobson
Regulatory Review by Neel Parmar
The FDA has been guiding manufacturers on how to "people-proof" their devices since 2016 through a guidance document titled Applying Human Factors and Usability Engineering to Medical Devices. This guidance finally brought the core FDA philosophy of risk-based oversight into the human factors world and focuses on the potential for misuse to lead to user harm. The latest update to this guidance now includes a second document titled Content of Human Factors Information in Medical Device Marketing Submissions. In conjunction, these fully explain testing processes and report content, each with distinct compliance expectations. The original document explains to manufacturers how to test their devices for human error, while the newer document details how to document and report these tests to the FDA. Even those who think they are exempt from HF testing in accordance with FDA exemption criteria are impacted, as they will need to justify their exemption rationale.
The testing guidance was the first of these documents, originally issued in 2016. The reporting document was eventually finalized in May of this year. But a key development this August removed the reporting template from the original testing guidance, directing applicants to the May reporting document instead.
With these actions, the FDA appears to have gotten closer to clarity and finality on how manufacturers should report their test findings to the agency. But even with this latest update that offers some standardization, the FDA is still signaling a potential shift from recommendation to requirement for human factors testing.
What Human Factors Testing Entails
Human factors validation testing has a few consistent expectations around who does the testing. The FDA generally recommends a minimum of 15 participants from each distinct user group. If a device is used by two different groups, say, nurses and patients, that means 15 people from each group. The number can be higher for certain device types, and the FDA leaves the final determination to the manufacturer.
That 15 figure isn't arbitrary. It traces back to research showing that a group of 15 caught at least 90 percent of known usability problems, with very little gained by adding more people. Doubling the group to 30 improved detection by less than two percentage points on average.
Participants should also be US residents, since the results are intended to demonstrate safe use in this country. Exceptions are considered on a case-by-case basis with a sound rationale. Employees of the manufacturer are generally excluded because of the bias they bring, with a narrow exception for devices whose only users are company personnel, such as installations or calibration processes handled exclusively by manufacturer representatives.
The most important expectation is the simplest one. Participants must use the device as a real person would, without coaching, and the assessment includes the product itself as well as its packaging and labeling.
Guidance Is Not Law, However
The FDA says as much on page one. This is among the biggest takeaways from the FDA's actions on device testing this year. They clarify that the use of the word "should" doesn't indicate a firm requirement. This, however, comes with a significant caveat, and it has nothing to do with the guidance itself.
Alongside both guidance documents, the FDA also updated the eSTAR submission templates. As of August 1, 2026, the non-IVD and IVD templates prompt manufacturers to identify their Human Factors Submission Category and to provide the supporting information associated with it. This makes the guidance optional in theory but unavoidable in practice because the form includes a field for it, and an FDA reviewer will review that field. This is what essentially makes the guidance compulsory, even without the FDA explicitly stating as much.
What the FDA Expects From Human Factors Testing
The underlying objective of human factors testing and the corresponding application submission is to ensure the device is properly designed, rather than to make the training manual more elaborate to mitigate user error. Sometimes a standalone safety mechanism is the next best alternative to better design, but the FDA knows that manuals are hard to follow, and training fades over time. Ease of proper use is essential to meeting the FDA's expectations.
Human Factors in QMSR
Human factors in Quality Management System Regulation are reflected in a device's usability, as determined by its design. QMSR standards took effect on February 2, 2026, replacing the FDA's old Quality System Regulation in 21 CFR Part 820. As the FDA has moved to harmonize with ISO standards, 21 CFR 820.7 incorporates ISO 13485:2016 by reference, making ISO 13485 the backbone of the requirement. Validating the device design is legally required under 21 CFR 820.10(c) and is spelled out more explicitly in ISO 13485 clause 7.3.7.
Manufacturers have to test their devices to confirm that they meet their intended uses. This is the essence of human factors testing.
That validation work is documented in the Design and Development File as part of design controls, which places it within the quality system rather than off to the side in submission prep. Without a single unifying document, completing the submission becomes a bit of a regulatory scavenger hunt for manufacturers.
Start With the Use-Related Risk Analysis
The URRA is the starting point and its output guides the entire HF process for your product. It is not a deliverable produced at the end. This analysis identifies critical tasks: user tasks that, if performed incorrectly or not performed, would or could cause serious harm. The presence or absence of such critical tasks is what determines the submission category, so the category is an output of the URRA.
A weak or late URRA can lead to initial submission mis categorization, and the wrong category will result in a deficiency. If the URRA is an afterthought to product design, a weak URRA and the resulting deficiency will be the most likely outcome, making risk analysis even more important to the product design phase and serving as a guiding voice in the development of a product’s regulatory strategy.
The Three Submission Categories
It's critical to understand that the submission category is determined by well-defined FDA criteria, and is not arbitrarily chosen by the manufacturer.
- Category 1 is for modified devices with no changes to the user interface, intended users or uses, use environments, training, or labeling. This is a high-level summary of the human factors evaluation.
- Category 2 is for new devices with no critical tasks, or modified devices with no new or impacted critical tasks. Documentation that includes a supporting rationale for that conclusion is usually necessary.
- Category 3 is for new devices that involve critical tasks, or modified devices in which updates create new critical tasks or significantly affect existing ones. Category 3 requires a full HFE/UE report including the URRA and critical task identification.
A submission falls into one category, with documentation increasing as use-related risk rises. The categories did not change from the 2022 draft, which is why the FDA's flowchart addition now matters more than the categories themselves for manufacturers.
The Impact of Decision Point D
This is the one substantive change to the FDA's risk-based flowchart between the 2022 draft and the May 2026 final guidance. This part sets out considerations for determining whether human factors validation testing should be included in the submission. Testing has effectively moved from premarket review to inspection.
This allows some applicants to justify omitting validation testing data from the marketing submission. With that said, the guidance itself notes that the information should still be maintained and may be reviewed during an inspection. The important distinction for manufacturers to consider is that Decision Point D changes what goes into the submission, not what goes into the Design and Development File.
What to Do Next With Your Human Factors Testing
Risk analysis is critical. The FDA is applying a risk-based approach across everything because it's how the agency removes unnecessary regulation and justifies what it keeps.
For manufacturers, this means the requirement is not meaningfully optional. The guidance describes how the FDA wants to see the work. The regulation already required the work itself. If you're preparing a submission now, follow the current guidance even where it reads as a recommendation. And if the FDA ever codifies these expectations through rulemaking, manufacturers already aligned to the guidance won't have to change anything.
Knowing which submission category applies to your device and what evidence must support that answer is the difference between a clean review and an avoidable deficiency. The team at Accorto Regulatory Solutions can help you get that right before you file.
Sources
Content of Human Factors Information in Medical Device Marketing Submissions, final guidance. Federal Register Doc. 2026-10734, published May 29, 2026.
https://www.federalregister.gov/documents/2026/05/29/2026-10734/content-of-human-factors-information-in-medical-device-marketing-submissions-guidance-for-industry
Applying Human Factors and Usability Engineering to Medical Devices, revised August 3, 2026. Original final February 2016.
https://www.fda.gov/regulatory-information/search-fda-guidance-documents/applying-human-factors-and-usability-engineering-medical-devices
Direct PDF: https://www.fda.gov/media/80481/download
eSTAR Program page.
https://www.fda.gov/medical-devices/how-study-and-market-your-device/estar-program
FDA town hall on the final guidance, held July 22, 2026. FDA held it for industry and other interested parties to discuss the final guidance. Useful as evidence FDA is actively fielding questions on category selection.
https://www.fda.gov/medical-devices/medical-devices-news-and-events/town-hall-content-human-factors-information-medical-device-marketing-submissions-final-guidance
Eric Jacobson
Marketing and Brand Manager
Eric Jacobson is the Marketing and Business Development Manager at Accorto Regulatory Solutions. He has spent 20 years in marketing for healthcare and other regulated industries, work that mostly comes down to making technical requirements clear to the people who have to meet them. His posts are reviewed by Accorto’s regulatory consultants before publication.
Neel Parmar
Regulatory Specialist I
A member of Accorto’s Regulatory Writing Team, Neel Parmar, recently graduated from Northeastern University with a Master of Science in Regulatory Affairs. His academic foundation was enriched by specialized coursework in regulatory compliance, strategic product lifecycle management, and advanced regulatory writing, preparing him to excel in complex regulatory documentation environments. Before his role at Accorto, Neel cultivated valuable experience as part of the team at Interscope Inc., contributing to the transition of a Class IIA medical device from MDD to MDR compliance. His role involved supporting the creation of critical regulatory documents and participating in comprehensive gap analyses to ensure alignment with MDR requirements.
