Why Human Factors Studies Are Critical for De Novo and SaMD Submissions

As medical devices become more software-driven, connected, and user-dependent, Human Factors Engineering (HFE) has become a critical — and often underestimated — part of FDA submissions. For De Novo and Software as a Medical Device (SaMD) products especially, FDA scrutiny around usability, workflow design, and real-world user interaction continues to increase.

Demonstrating that a device functions technically is no longer enough. Manufacturers must also prove that intended users can operate the product safely, correctly, and consistently in real-world conditions.

Human Factors Is Fundamentally About Patient Safety

De Novo submissions often involve novel technologies, new workflows, and limited predicate history. Without established usability precedents, FDA reviewers place greater emphasis on:

User interaction design
Software workflows
Label comprehension
Risk mitigations
Training assumptions
Critical task performance

In many cases, the FDA is ultimately asking one question: Can real-world users operate this product safely without creating unacceptable risk?

SaMD Introduces Unique Usability Risks

SaMD products introduce additional Human Factors challenges because users interact with software interfaces, AI-generated outputs, dashboards, mobile applications, remote monitoring systems, and clinical decision support tools.

Unlike traditional hardware devices, SaMD usability failures often involve:

Cognitive overload
Workflow confusion
Alert fatigue
Misinterpretation of results
Incorrect configuration
Data presentation issues

These risks are not always apparent during development. Human Factors studies help uncover where real users struggle before those issues reach the market.

Human Factors Is More Than Usability Testing

A common misconception is that Human Factors studies are simply user satisfaction exercises. They are not.

FDA-focused Human Factors validation is a risk-based process tied directly to:

Design controls
Risk management
Intended use
Critical task identification
Safety mitigations

Manufacturers are expected to identify potential use errors, root causes, use-related hazards, and whether residual risks remain acceptable. This is fundamentally a patient safety exercise — not a UX review.

Critical Tasks Drive Study Design

Critical tasks are actions that, if performed incorrectly, could lead to patient harm, delayed treatment, misdiagnosis, or unsafe conditions. For SaMD and connected devices, these often include:

Entering patient data correctly
Interpreting AI-generated recommendations
Selecting the correct workflow
Responding appropriately to alerts
Configuring device settings

If critical tasks are not properly evaluated, FDA reviewers may question whether the study adequately demonstrates safe use.

Knowledge Tasks Are Becoming Increasingly Important

For consumer-facing and AI-enabled products, the FDA is placing growing emphasis on “knowledge tasks” — evaluating whether users understand device limitations, warning messages, software outputs, and when medical intervention may be required.

This is particularly important for:

Consumer-facing SaMD
OTC products
Remote monitoring systems
Wellness-to-medical transitions
AI-enabled platforms

A technically correct output still creates risk if users misunderstand what it means.

Human Factors Findings Often Reveal Larger Design Issues

Well-executed Human Factors studies frequently uncover broader product weaknesses, including:

Confusing workflows
Weak IFUs
Poor onboarding
Risk management gaps
Overcomplicated interfaces
Incorrect assumptions about users

Companies that treat Human Factors as a late-stage checkbox often miss opportunities to improve both product quality and regulatory readiness.

Common Human Factors Mistakes

Some of the most common issues seen during FDA preparation include:

Starting Human Factors planning too late
Poor critical task identification
Testing unrealistic use environments
Evaluating the wrong user population
Weak knowledge assessments
Missing traceability between risks and mitigations

These issues can create significant review delays if identified during FDA evaluation.

Human Factors Should Begin Early

Human Factors activities should begin during product design, workflow development, software architecture planning, and risk analysis — not during submission preparation. Early identification of usability risks makes mitigation far more effective and significantly reduces late-stage remediation.

FDA Expectations Will Continue to Grow

As healthcare becomes more digital, decentralized, and consumer-facing, FDA expectations around Human Factors will continue to expand — particularly for:

AI/ML-enabled devices
Connected platforms
Remote monitoring systems
Home-use devices
SaMD and digital therapeutics

Manufacturers should expect increasing scrutiny around how users interact with these technologies in realistic environments.

Final Thoughts

Human Factors studies are no longer optional formalities for De Novo and SaMD submissions. They are a critical part of demonstrating safety, effectiveness, and real-world usability.

Companies that integrate Human Factors early are typically better prepared for FDA review, more successful at identifying usability risks, and better positioned for commercialization success.

Ultimately, a successful medical device is not just one that works technically — it is one that users can safely and correctly use in the real world.

Need Help Planning a Human Factors Study?

RQMIS supports medical device, IVD, SaMD, AI-enabled, and connected device companies with Human Factors strategy, usability engineering, risk management integration, protocol development, simulated-use studies, and FDA-ready validation reporting.

If your organization would like to discuss a Human Factors strategy for an upcoming FDA submission, our regulatory and clinical teams can help evaluate your workflow, intended users, critical tasks, and regulatory pathway goals.