Perfecting your Human Factors / Usability Engineering File
Best Practices for Creating and Updating your HFE/UE File
At Core Human Factors, our clients often reach out to us with questions regarding their human factors engineering / usability engineering file (UE file). Guidances and standards from both domestic and international regulatory bodies reference a wide array of studies, methods, and documents that can be a part of your human factors design process depending on your needs and your product’s risk profile. Determining which methods to utilize can be challenging, and understanding how to structure a UE file can be confusing and difficult.
What is a HFE / UE file?
A UE file can be anything you need it to be, and this is perhaps the crux of the confusion. For example, a UE file could be a large collection of physical, printed documents in their full and final form. Alternatively, a UE file could be a short document that simply contains a list of references to other documents. FDA and ANSI/AAMI/IEC 62366 do not specifically regulate how a UE file is curated or the form in takes. What is much more important is that the UE file is complete and up-to-date.
62366 details methods and standard processes for usability engineering for medical devices, and states that compliance with the standard is “checked by inspection of the usability engineering file.” For FDA submissions, the presence of a HFE/UE summary report is essential. This report alone dictates the need for various other evaluations to be completed, such as a use-related risk analysis and a HF Validation study. Beyond that, the contents of the file is left to the discretion of the manufacturer.
For some of our clients, the most effective strategy is to create a single, literal, file that serves as the resting place for HFE / UE related materials, including protocols, tests, evaluations, data, reports, and post-market data. Other clients are best served by limiting their UE file to a collection of references to various final documents. The goal of this article is to provide tips for creating a comprehensive HFE / UE report. However, the feasibility and necessity of all possible UE file components is dependent on your product’s risk profile, history (e.g., a third-, fourth-, or twentieth-generation product may not require the same detail as a novel device), and the needs and resources of your company.
What goes in a HFE / UE file?
Your UE file should illustrate the iterative human-centric design process your product has gone through, with a focus on safety and risk. We often find it helpful to begin with a document that defines your users, use scenarios and use environments. From there, you are better equipped with the perspective necessary to create a use-related task and risk analysis (URRA). This type of analysis breaks down the workflow required to use your product as intended into distinct tasks, and outlines what inputs are required from the user (e.g. what they need to know, do, and sense in order to complete the task as intended), and what possible outputs might occur. “Possible outputs” should include use errors that might occur, and, perhaps most importantly, all possible risks associated with those use errors and a measure of how severe those risks are. Lastly, this URRA should keep track of your mitigations for each potential use error. Remember: these documents are dynamic, and your understanding of your product’s potential risks may evolve over time as you conduct more testing and implement design modifications.
These documents pave the way for running effective formative usability tests. There are many types of formative tests you can implement to learn about the successes and shortcomings of your user interface design. Your UE file should contain a record of these tests, and particular attention should be paid to how the results of these tests informed design changes and eventually the protocol for your HF Validation (or Summative) test.
Next, the file should contain the protocol, materials and report from your HF Validation test. The HF Validation provides the primary empirical data a company uses to draw conclusions about the safety and effectiveness related to use of their Product. However, other HF formative tests and other components of the UE file may be requested for review by domestic and international regulatory bodies. Finally, as previously mentioned, your file will need your HFE/UE summary report to submit to FDA.
As a note, many clients overlook their instructions for use (IFU) development. As part of the overall user interface and submission, your IFU will be part of your HF Validation report. Therefore it can be extremely valuable to include the IFU in your HF testing as early as possible and to optimize it through iterative testing. Similarly, other labeling such as product packaging is also part of the overall user interface and submission, and usability issues related to product packaging should be considered, and tested for, as early in the design process as possible.
What happens to a HFE / UE file?
Some pieces of the file will be reviewed by regulatory bodies as a part of your submission. It is possible that once the product is on the market your UE file might gather some dust. However, it can be useful to keep track of use-related post-market data there. This may include use-related product complaints or reports of adverse events that shed light on potential design issues with the product. For example, if you choose to make design modifications to the user interface after your product is on the market, you can validate those changes with a HF test that is limited to testing the modifications.
Beyond regulatory purposes, the UE file can be of interest to various stakeholders. The file can help interested parties understand the design process that the product underwent, the rationales for various decisions, and proof of due diligence to comply with standards and regulations.