Human factors studies and usability engineering are critical elements in the safe, effective, and user-centered design of medical devices. These disciplines ensure that devices are intuitive, reduce the likelihood of use errors, and support positive patient outcomes. Importantly, they also help manufacturers meet the expectations laid out in FDA guidance on human factors and usability engineering, making the device development process smoother and more compliant.

This article summarizes the key aspects of the FDA’s guidance and how human factors engineering (HFE) and usability engineering (UE) can help medical device manufacturers conduct thorough use-related risk assessments, perform essential validation studies, and produce devices optimized for real-world use.

FDA Guidance Overview: Applying Human Factors in Medical Devices

The FDA’s guidance document—“Applying Human Factors and Usability Engineering to Medical Devices”—was released in 2016 to help manufacturers integrate HFE/UE into the design and development of medical devices. The guidance outlines how to account for user capabilities and limitations, and how to proactively identify potential use-related hazards that could affect safety and effectiveness.

The document provides direction on how to conduct human factors studies, emphasizing that device safety is best ensured when usability is addressed early and often during product development.

Key Definitions for Human Factors and Usability Engineering

Before diving deeper, it’s helpful to define a few foundational terms used throughout HFE/UE processes:

• Abnormal Use: Intentional or reckless use contrary to instructions.
• Critical Task: Any task that could result in harm if performed incorrectly or not performed at all.
• Use Error: An unintentional action or lack of action by the user that leads to a different result than intended. 
• Hazard: A potential source of harm associated with using or misusing a medical device. 
• User Interface: The elements of a medical device that users interact with, such as buttons, labels, or even packaging. 
• Validation testing: A study that evaluates whether medical devices can be used safely and effectively by their intended users in their intended environments. It focuses on critical tasks and mitigating potential use-related risks.

Human Factors Engineering in Medical Device Design

Human factors engineering examines how people interact with technology, particularly in complex environments such as healthcare. In medical device design, HFE ensures that devices are intuitive, easy to use, and effective—regardless of the user’s training level or environment.

At its core, usability engineering for medical devices focuses on designing products that reduce the risk of use errors. It takes into account:

• Intended Users: Healthcare professionals, patients, or caregivers.
• Use Environments: Hospitals, homes, ambulances, etc.
• Device Interfaces: Labels, alarms, buttons, displays, and controls.

By designing with these factors in mind, manufacturers reduce the likelihood of hazardous situations and improve device outcomes.

Device Users, Use Environments, and User Interface

At the outset, HFE/UE approaches consider the medical device’s intended users, use environments, and user interfaces. For example, intended users might be patients, caregivers, and/or medical professionals. Considering how each group brings different knowledge and experience to device use is key to effective design. Varying environments can also impact how devices might be used. Different environments to consider may include hospitals, homes, or emergency settings. When designing user interfaces, manufacturers should consider the wide range of users and environments to create an intuitive experience in various circumstances.

Conducting Use-Related Risk Assessments

A key requirement of the FDA’s guidance is the performance of a thorough use-related risk assessment. Early in development, manufacturers must identify and categorize critical tasks—the actions users must perform correctly to avoid harm.

Strategies include:

• Task Analysis: Breaking down each step of use to identify hazards.
• Simulated-use testing: Observing users in realistic scenarios to reveal potential risks.
• Iterative design: Continuously refining the interface based on findings.

These evaluations are essential in developing safe and effective medical devices that meet FDA risk assessment expectations.

Eliminating or Reducing Use-Related Hazards

After identifying hazards, the next step is to mitigate them. The most effective mitigation strategies are built directly into the design, rather than relying on training or labeling. Examples include:

• Design modifications to reduce complexity.
• Interlocks, barriers, or guard mechanisms.
• Clear, accessible instructions and visual cues.

These actions are not only best practices—they align directly with FDA guidance on human factors engineering.

Human Factors Validation Testing for FDA Submission

Human factors validation testing (also called summative usability testing) is conducted near the end of the development cycle. Its purpose is to confirm that intended users can use the device safely and effectively in the actual environments where it will be used.

Validation studies must:

• Include a representative sample of intended U.S. users.
  
• Focus on the successful completion of critical tasks.
  
• Simulate real-world scenarios as closely as possible.

This step is essential for a successful 510(k) submission or premarket approval (PMA), and helps ensure that devices are not only compliant but also ready for commercial use.

Documentation Requirements for FDA Review

Thorough and organized documentation is critical for FDA submissions. Manufacturers must provide:

• A summary of the human factors engineering process.
• Detailed risk analyses.
• Validation testing results and conclusions.
• Justification for design decisions.

This documentation demonstrates that usability engineering for medical devices has been properly implemented and that risks have been identified and mitigated in line with regulatory expectations.

Don’t Overlook the FDA Appendices

Don’t overlook the appendices in the FDA’s guidance on human factors and usability engineering. They are valuable resources for manufacturers preparing a 510(k) submission. The appendices feature report templates to streamline documentation, considerations for determining appropriate sample sizes, and methodologies for analyzing validation testing results. 

Key Takeaways for Medical Device Human Factors

Here are the five top takeaways when it comes to HFE/UE for your medical device:

1. User-Centered Design from the Get-Go – Human factors engineering should be integrated throughout the design and development process to minimize use-related risks and improve usability.
2. Identification of Critical Tasks – Manufacturers must identify critical tasks—steps where user errors could lead to serious harm—and ensure the design mitigates these risks.
3. Iterative Testing and Risk Management – Human factors efforts should be iterative, using formative studies to refine design and ensure usability-related risks are adequately controlled.
4. Human Factors Validation Testing is Required – A final summative test must evaluate the medical device in realistic conditions to confirm that intended users can operate it safely and effectively.
5. Comprehensive Documentation for FDA Submission – Manufacturers must submit a report detailing the design process, risk analysis, test results, and justification for safety-related decisions.

Partner with Experts to Navigate Human Factors Compliance

While FDA expectations can seem daunting, they are designed to promote safer, more effective products. Working with a research partner like SoundRocket, experienced in medical device human factors studies, helps ensure that your product meets regulatory standards while staying user-focused.We help guide manufacturers through the entire HFE/UE process—from formative research to FDA-compliant human factors validation testing—resulting in better design, faster approvals, and safer devices for users everywhere.