Human factors engineering focuses on researching, designing, and evaluating products to make them useful, usable, desirable, and safe.

Healthcare human factors engineering emphasizes safety. In fact, during the premarket submission process, the U.S. Food and Drug Administration (FDA) requires manufacturers to demonstrate that their devices, combination products, and in-vitro diagnostics can be used safely and effectively before they grant medical device approval.

Our work falls squarely in this area, addressing two important challenges. We must ensure that medical products are indeed useful, usable, desirable, and most importantly, safe. The second challenge is helping clients prove said safety to regulatory agencies, such as the FDA, through their submissions. Our experience in assisting and directing these submissions has led us to discover some tips that we think are useful.

FDA Human Factors Guidance

Before counting down the tips, let’s discuss the FDA Human Factors Guidance. In 2016, the FDA’s Center for Devices and Radiological Health (CDRH) published “Applying Human Factors and Usability Engineering to Medical Devices: Guidance for Industry and Food and Drug Administration Staff.” Usually, we call it the “FDA Guidance”. FDA released it to help the industry follow a strong human factors engineering process so that devices are safe and effective.

We developed the following graphic to illustrate the process outlined in the FDA Guidance. We divide it into three main steps, each with substeps. The first step involves identifying and characterizing your users, use environments, interfaces (including IFU, packaging, etc.), known issues, and critical tasks. We typically identify critical tasks through a use-related risk analysis (URRA). This analysis entails breaking down each task into its component subtasks and then evaluating where difficulties and use errors might arise. Then we update it throughout product development.

The second step entails conducting a series of iterative usability tests (formative tests) to uncover and remedy potential usability problems. The goal is to uncover as many usability problems utilizing as little money and time as possible.

The third and final step entails conducting a validation usability test. The validation study demonstrates to the FDA that the product does not present an undue risk of harm to the user or patient. The validation testing should include a minimum of 15 users per group and should evaluate all of the device’s critical tasks identified in the use-related risk analysis.

Although the process is reasonably simple, the devil, as they say, is in the details. As we have employed FDA’s Human Factors Guidance repeatedly, we have discovered the following tips to make the submission process and medical device approval less daunting.

Tip 1. Include All User Groups in Your Analysis, Testing, and FDA Human Factors Submission

Manufacturers often fail to recognize all of the distinct user groups they have. Each group may have different characteristics (e.g., training, reading abilities, experience) or may conduct different tasks. Consider a complex surgical system, for example. One user is obviously the surgeon, but a nurse might conduct another set of tasks with the product, and the reprocessing technician may conduct a third set of tasks.

Each group’s backgrounds, needs, activities, and risks may be different. As a result, you might have three or four user groups rather than just one. It is critical to be aware of this early on because you can be sure that the FDA will recognize this upon submission. Failing to include all user groups can result in the need to conduct additional analyses and usability testing, leading to submission delays. To make sure you consider all the user groups, ask yourself these questions:


  • …purchases the device?
  • …receives the device?
  • …unpacks the device?
  • …sets up the device?
  • …uses the device?
  • …cleans or reprocesses the device?
  • …disposes of the device?

Tip 2. Identify all User Interface Components

Manufacturers often think of user interfaces as visual displays. They forget that the FDA Human Factors Guidance considers user interfaces as “all points of interaction between the product and the user(s) including elements such as displays, controls, packaging, product labels, instructions for use, etc.” As such, you should make sure to include all points of interaction in your Human Factors engineering analyses and subsequent testing.

Tip 3. Be Thorough in Identifying all Known Use-Related Hazards

Known issues refer to usability problems identified from previous versions of the device, predicate devices, or similar devices. This is the FDA’s way of telling you not to make the same mistake twice. Identifying usability issues with current and previous devices helps avoid those problems. There are many ways to uncover known issues, such as:

  • Internal customer feedback and complaints
  • Sales representatives and clinical support staff
  • Observing or interviewing current users

Many resources can be used to identify potential use-related hazards. Be sure to check out the ones below:

Tip 4. Make Sure You Identify All of the Critical Tasks

The FDA Human Factors Guidance defines a critical task as a user task that, if performed incorrectly or not performed at all, would or could cause serious harm to the patient or user. Critical tasks should be determined from severity scores given in the URRA or failure modes and effects analysis (FMEA). While the risk analysis traditionally combines severity and probability to assign a risk score, critical tasks should be determined using only their potential severity of harm. In short, any task that could lead to harm, regardless of the likelihood of occurrence, should be identified as a critical task.

Tip 5. Do Formative Usability Tests Early, Often, Quickly, and Economically

As a product’s user interface takes shape, you should conduct formative usability tests to improve the user interface by identifying and remedying usability problems quickly and iteratively. Formative testing can also be performed throughout the design process to help decide between multiple options and ensure the decisions being made meet the user’s needs.

Formative usability tests are not officially mandated nor reviewed by any of the regulatory agencies. Therefore, there are no requirements for the number of participants included in formative usability tests. Often, as few as five to seven participants may provide sufficient data to determine where the design needs improvement.

The user interface does not need to be finalized before formative usability testing. The whole idea of formative testing is to evaluate whether the user interface design is appropriate and to revise the design based on findings.

Lastly, iterative formative testing is critical to successful design. Think of it as debugging the user interface. With sufficient debugging, through iteration, the system product becomes safer. Then, by the time you conduct validation testing, you will be supremely confident in the validation results. When formative testing has been done diligently, the validation test begins to feel like a victory lap!

Suprise Tip: Consider an Hiring an Expert

By following these five tips, you will be on your way to making the FDA submission process more manageable. To ensure a successful submission, our last tip would be to bring in Human Factors Experts who can guide you through the process and help save you time, stress, and money by putting these tips and their expertise into practice. We at Research Collective pride ourselves on our track records of successful FDA submissions, and would be happy to assist you in your next project.

Contact us to learn how our FDA Human Factors Guidance expertise can help you streamline the FDA submission process and obtain medical device approval.