Designing for the Unseen: What Human Factors Can Teach Us About Better Devices

Why Understanding Human Behaviour is Key to MedTech Innovation 

In the world of medical devices, we often celebrate engineering ingenuity and precision. But what if the most important design insights lie not in the obvious – the device itself – but in the subtle, unseen ways people interact with it? 

The field of human factors engineering urges us to look beyond functionality and ask a different set of questions: How do people actually use this device? What mental shortcuts do they take under pressure? What happens when they are tired, distracted, or overwhelmed? What assumptions are we making about users that may not be true in real-world settings? 

These “unseen” variables, often invisible in traditional design processes, can have life-or-death consequences in healthcare. They also hold the key to building better, safer, and more intuitive technologies. 

Are Human Factors the Missing Link in Medical Device Design?

Human factors is the science of understanding how people interact with systems, tools, and environments, and designing for those interactions. In healthcare, it is about reducing user error, improving safety, and creating devices that work in the chaotic, fast-paced reality of clinical practice. 

It is not about blaming the user. It is about acknowledging that humans are fallible and designing with those fallibilities in mind. 

Consider this: a perfectly functioning infusion pump that requires five steps to program might still be dangerous if nurses routinely skip steps under time pressure. Or a wearable sensor with sleek functionality might go unused if patients do not understand how to charge it or interpret its data. 

Human factors fill this critical gap – the space between technical capability and actual usability. 

How to Design Medical Devices for Clinicians, Patients, and Carers? 

One of the biggest traps in medical device design is assuming that users are always well-trained, alert, and following protocol. But the reality is far messier. 

• Clinicians are interrupted, multi-tasking, and making rapid decisions. 

• Patients might have low health literacy, limited mobility, or cognitive impairment. 

• Carers could be non-medical family members trying to follow instructions at home. 

Human factors research helps uncover these realities through tools like usability studies, contextual inquiry, and task analysis. It shifts the focus from how a device should be used to how it will be used, and by whom. 

It also accounts for variability. Not every user will interpret a touchscreen the same way. Not every nurse will respond to an alert tone the same way in a noisy ward. Human-centred design embraces this variability instead of trying to eliminate it. 

What Human Factors Cause Medical Device Errors?

Despite increasing regulation around usability, design flaws related to human factors remain a top cause of medical device recalls and failures. 

Common “unseen” issues include: 

• Ambiguous visual feedback: Lights, icons, or sounds that do not clearly signal device status or next steps. 

• Mental model mismatches: When the way users expect a device to work does not match how it actually functions. 

• Cognitive overload: Interfaces that demand too much attention, memory, or decision-making in high-pressure environments. 

• Poor accessibility: Text that is too small, buttons that are too close together, or assumptions about dexterity or vision. 

These may sound like minor design flaws, but in healthcare, they can have serious consequences. A misread button, a missed alarm, or a misunderstood interface can lead to medication errors, missed diagnoses, or patient harm. 

How to Design Medical Devices for Home Healthcare?

As more care shifts to the community and home settings – driven by cost pressures, an ageing population, and the rise of remote monitoring – the need for human factors grows exponentially. 

Devices are no longer used only by trained professionals in controlled settings. Instead, we are asking patients and carers to take on clinical tasks: injecting insulin, managing wound care, or using telehealth devices. 

Designing for these users means rethinking assumptions: 

• Do users have internet access or digital literacy? 

• Can they understand medical terminology? 

• What is the lighting, noise level, or distractions like in their home? 

• Are instructions culturally appropriate and available in multiple languages? 

The unseen context of someone’s life can determine whether a device empowers them or overwhelms them. 

How Can Usability Testing Improve Medical Device Adoption?

Human factors should not be an afterthought or a regulatory checkbox. It must be embedded from the start in every design sprint, prototype review, and testing phase. 

Here is how: 

1. Start with ethnographic research 
   Spend time observing real users in real environments. Watch how they interact with existing devices, where they hesitate, and where workarounds emerge. 
2. Use formative usability testing early
   Test prototypes with representative users before design decisions are locked in. Capture both verbal feedback and behavioural cues. 
3. Build diverse personas 
   Design for a range of physical abilities, digital literacy levels, and cultural backgrounds. Avoid the “average user” fallacy. 
4. Iterate with feedback loops 
   Allow time and budget for multiple rounds of testing and refinement. Usability is not a one-off event. 
5. Simulate real-world scenarios 
   Test under stress, noise, or time constraints – not just in quiet labs. 
6. Train your team in human factors 
   Cross-functional teams, especially engineers, benefit from a shared understanding of human-centred design principles. 

Integrating human factors into each of these stages is not only essential for safety but also delivers measurable business value. Devices that are intuitive and difficult to misuse tend to secure regulatory approvals more efficiently, face fewer post-market issues, and are less likely to be recalled. The FDA has highlighted that a significant share of device recalls stem from use-related errors – many of which could be prevented through proactive usability testing. In practice, medical technologies designed with users in mind consistently see stronger uptake by clinicians and patients alike, leading to greater trust, improved outcomes, and enhanced market success. 

Are You Meeting FDA and IEC Human Factors Requirements?

Regulators are increasingly recognising the importance of human factors. Standards like IEC 62366-13 and the FDA’s human factors guidance demand usability engineering in medical devices. But regulation can only go so far. 

Compliance does not guarantee good design – it guarantees minimum safety. True innovation means going further: designing devices that reduce cognitive burden, and feel intuitive even in moments of stress or fatigue. 

The best design teams treat human factors not as a hurdle but as a source of insight. They ask: What can go wrong here? Where might the user make a mistake – and how can we design around it? 

Conclusion: Designing for the Seen and the Unseen

Human factors remind us that good design is about empathy, not just engineering. It is about stepping into the shoes of the overworked nurse, the confused patient, the frustrated carer, and building solutions that support them. 

In doing so, we do not just reduce error. We build trust, improve adherence, and unlock the true potential of technology to improve lives. 

In the end, it is not just about what the device does. It is about what the user needs and how we design for that. 

References

• Mbbs, G. and Mrcs, B. (n.d.). Understanding the influence of health information technology on quality and safety in secondary care A thesis presented for the degree of Doctor of Philosophy (PhD). [online] Available at: https://core.ac.uk/download/217979729.pdf
• Gosbee, J. (2002). Human factors engineering and patient safety. Quality and Safety in Health Care, 11(4), pp.352–354. doi: https://doi.org/10.1136/qhc.11.4.352 .
• International Electrotechnical Commission (IEC). (2015). IEC 62366-1: Application of Usability Engineering to Medical Devices.
• FDA. (2016). Applying Human Factors and Usability Engineering to Medical Devices: Guidance for Industry and Food and Drug Administration Staff.

Disclaimer. The views and opinions expressed in this article are solely those of the author and do not necessarily reflect the official policy or position of Test Labs Limited. The content provided is for informational purposes only and is not intended to constitute legal or professional advice. Test Labs assumes no responsibility for any errors or omissions in the content of this article, nor for any actions taken in reliance thereon.