NEW FDA Guidance on Human Factors Engineering for Combination Products!

Sep 25, 2023 | News |

NEW FDA Guidance on Human Factors Engineering for Combination Products!Introduction to the Final Guidance

FDA recently published a final guidance document, “Application of Human Factors Engineering Principles for Combination Products: Questions and Answers.”  This question-and-answer formatted document aims to clarify and provide additional guidance on the human factors engineering (HFE) process during combination product development, originally established in the February 2016 draft “Human Factors Studies and Related Clinical Study Considerations in Combination Products Design and Development.”

The guidance, released 7 years after the initial draft, addresses concerns about the overlapping requirements between the medical device and drug industries for human factors engineering. The draft from 2016 needed clarity on what the differences were between the draft and FDA’s previously released guidance “Applying Human Factors and Usability Engineering to Medical Devices.” Although this final guidance references “Applying Human Factors and Usability Engineering to Medical Devices” throughout, it clarifies definitions on combination product and addresses questions that may come up during combination device development regarding human factors. Some crucial topics highlighted also include combination product critical tasks, user-related risk analysis (URRA), user-interface considerations, and HF validation data.

This guidance represents FDA’s current thinking on the HFE process and principles throughout combination product development and lifecycle changes. In addition to the previous draft version, this document supplements other guidance documents, “Applying Human Factors and Usability Engineering to Medical Devices,” “Safety Considerations for Product Design to Minimize Medication Errors,” and those released by FDA Centers describing other aspects of product development. Any products that are not a combination product, or a combination product that does not include a medical device falls outside of the scope of the guidance.

Guidance Content

The HFE process focuses on applying available information and knowledge of human behavior to ensure the design of the user interface leads to safe and effective use of the device. The design of user interfaces has a direct impact on how a user interacts with the product.

Combination Product Critical Tasks & User-Related Risk Analysis

Part of the HFE process includes identifying combination product critical tasks, or tasks that unless performed correctly, could lead to harm to the user. The combination critical task definition is similar to the stand-alone device critical task definition; however, it differs in the level of harm as user-related risks associated with combination products may not exist for the independent device or drug.

The guidance document recommends creating a user-related risk analysis (URRA)to identify these critical tasks and potential hazards, which help estimate risk in combination products. A URRA evaluates all tasks with a focus on the harms associated with, but not limited to, intended use, use environment, and user hazards. Special attention should be focused on tasks that impact dosage, administration of the product, add potential harm, or are time sensitive.

Although the URRA is a subsection of the whole risk analysis, the guidance emphasizes that FDA recommends a separate submission of the URRA.  Several hypothetical examples of some combination product critical task considerations are provided within the guidance document.

User Interface Considerations

HF validation studies are used to ensure the user interface has been optimized to minimize risk associated with the user. Guidance dictates a HF validation study typically is conducted before the market application is submitted. The HF validation study results should be analyzed to determine if there are still user-related risks that justify modifying the product. If modification of the product is required to minimize risk, iterative HF validation studies must be conducted, and the new URRA should include all aspects of the combination product that may be affected by the change.

The FDA will analyze the HF validation study results as part of the market application to determine if they agree that user-related risks were sufficiently mitigated. If the HF validation study is not conducted with the finished and final product, justification for that choice must be provided.

It is also important to determine during HFE development if training should be part of the user interface based on the intended users, use environments, and use of the combination product. If training is part of the user interface design requirements, then the FDA recommends the training program be validated to ensure consistency and reliability. If training is not part of the user interface design requirements, the combination product user interface should be safe and effective without training.

Human Factors Validation Data

In particular cases, an HF actual-use validation study is applicable due to how complicated the combination product is or if a simulated-use study is insufficient. HF actual-use validation studies differ from simulated-use studies by administering medical care to the patient. This guidance document notes that the purpose of actual-use clinical studies is different from the purpose of HF actual-use validation studies.  If there are plans of running an HF actual-use validation study as part of an actual-use clinical study, the FDA recommends submission of the plans for review and guidance prior to the clinical trial.

Formal HF evaluation should take place throughout the entire product development process to identify user needs and how user interface affects user interaction. FDA will review formal HF evaluations for background information to support the draft HF validation study protocol as well as within the market application submission. Early and ongoing conversations about the HFE process with the FDA are critical and will help highlight which HF studies are necessary for submission.

At MEDIcept, we have leading experts that are qualified to help with your HFE needs, despite the phase of the product development process. Learn more about how MEDIcept can help you tailor your HFE process to best fit current regulations and standards. Contact us today at

For quick reference – a comprehensive list of questions addressed in the guidance document:

  1. What guidance is available for medication error considerations to inform the design of a combination product?
  2. Could a drug’s properties affect how a user interacts with a combination product that includes that drug?
  3. How do the general definitions in the guidance for industry and FDA staff Applying Human Factors and Usability Engineering to Medical Devices apply to a combination product?
  4. What is the definition of a final finished combination product?
  5. What is the definition of a combination product critical task and how are combination product critical tasks identified?
  6. How does FDA evaluate HF validation study results?
  7. Is there a difference between the use-related risk analysis (URRA) to support the user interface and other types of risk analysis?
  8. What considerations may apply for training as part of the user interface for combination products?
  9. What is the difference between an HF actual-use validation study and an actual-use/clinical home-use study?
  10. Are there any considerations for formative HF evaluator and the studies are not HF actual-use studies?
  11. What HF information and/or data should be provided to support initiating clinical investigations for a combination product?
  12. Does FDA expect the HF validation study that supports market authorization to be conducted at a certain development phase of the combination product?
  13. What HFE principles should be considered when modifying a combination product?
  14. What are FDA review processes for combination product draft HF validation study protocols and draft labeling?
  15. How do I obtain information from and provide information to FDA on my combination product HF program?


U.S. Food and Drug Association. (2023, September). Application of Human Factors Engineering Principles for Combination Products.

Sarah Boynton & Emily Sawtell – Associate Medical Device Consultants