User-centered design (German: Nutzerzentrierte Gestaltung) is an iterative design approach that puts the needs, abilities, and context of users at the center from the very beginning. ISO 9241-210 describes it as human-centered design. For medical devices, this approach complements the safety-oriented usability engineering process with a holistic user perspective that goes beyond mere error avoidance.
The core principles according to ISO 9241-210
User-centered design rests on a few principles that are pursued consistently: The design is based on an explicit understanding of users, their tasks, and their context, not on assumptions made by the development team. Users are actively involved throughout the entire process, not only at the end for sign-off. The design is driven by user-centered evaluation, meaning that design decisions are checked against real user reactions, not against internal preferences. The process is iterative, takes the entire user experience into account rather than only individual operating steps, and is carried by interdisciplinary teams that bring together technical, design, and domain knowledge.
These principles work together as a corrective against a common development dynamic: Teams tend to settle on a solution early and then look for confirmation of it. User-centered design demands the opposite: the willingness to actually discard or fundamentally change a solution based on user reactions, even late in the process.
The iterative design cycle
The approach is divided into four repeating phases: understanding the context of use, deriving requirements, developing design solutions, and evaluating the solutions against the requirements, usually with real users. After the evaluation, the cycle begins again, refined by the insights gained, until the requirements are met.
The shortness of the individual cycles is decisive here: The earlier and more often user feedback is obtained, the cheaper it is to correct misjudgments. A single large test cycle shortly before the end of development, user-centered design in name only, misses the actual value of the approach, because at that point fundamental changes are hardly economical anymore.
User-centered design and usability engineering
Both approaches overlap considerably but differ in orientation and in the obligation to provide evidence. The usability engineering process according to IEC 62366-1 is primarily safety-oriented: It aims to identify use errors and reduce their risk to acceptable levels, and it requires a documented, verifiable demonstration of this reduction.
User-centered design pursues a broader goal: not only safety but also efficiency, satisfaction, and an overall positive user experience. These aspects do not necessarily have to be demonstrated for regulatory purposes, but they matter considerably for acceptance and market success of a product. In practice, both approaches can be run in a single shared process: The iterative cycles of user-centered design deliver the formative insights that the usability engineering process requires anyway, while the safety orientation of IEC 62366-1 ensures that the iterative design does not bypass the safety-relevant requirements.
Why the holistic goal matters in medical technology
A product that provides every safety evidence required by regulation but is perceived by users as cumbersome, unpleasant, or not very trustworthy has a real problem that purely safety-oriented metrics do not capture: low acceptance, poor adherence to therapy for patient-facing products, or workaround behavior among professional users who, under time pressure, develop their own unplanned shortcuts.
Such workaround behavior is delicate from a regulatory perspective because it often concerns exactly the cases that have to be reassessed as foreseeable use in the use-related risk analysis. An approach that aims from the start at satisfaction and real-world practicality, rather than only at freedom from errors in the test, reduces the likelihood that users develop their own unplanned and therefore uncontrolled solutions in the field.
Organizational prerequisites
User-centered design succeeds only if contact with users is organized not as an isolated test phase but as a continuous project activity. This requires that access to representative users is possible early and repeatedly, a logistical challenge especially with specialized medical professionals whose time is limited.
Equally important is the organizational willingness to actually implement insights from early cycles in design changes rather than ignoring them for reasons of time or cost. An iterative process without genuine willingness to change creates the appearance of user centering without realizing its actual benefit.
Regulatory reference
ISO 9241-210 describes the general principles of human-centered design of interactive systems and is applicable across industries; it complements the more specific requirements of IEC 62366-1 with a broader design philosophy without itself setting requirements under medical device law. Annex I of the EU Medical Device Regulation (MDR) requires consideration of ergonomic features, the intended users, and the environment of use; a consistently user-centered development approach helps manufacturers integrate these requirements systematically into product development.
The iterative formative cycles of user-centered design can be used directly for the formative evaluations required by IEC 62366-1. The FDA Human Factors Guidance recommends formative evaluations during development. It treats serious use errors in human factors validation testing as a possible indication of insufficient analysis and formative evaluation.
User-centered design puts user needs, abilities, and context at the center of an iterative design process from the start, with a broader goal than mere error avoidance: efficiency, satisfaction, and real-world practicality.
For medical devices, the approach can be well integrated with safety-oriented usability engineering according to IEC 62366-1. The iterative cycles deliver the required formative insights without requiring a separate process.
Frequently asked questions (FAQ)
Is user-centered design required by regulation for medical devices?
Not directly. ISO 9241-210 is not a mandatory standard for medical devices under regulation. However, many of its principles support meeting the requirements of IEC 62366-1, ISO 14971, and the MDR, in particular regarding consideration of users, contexts of use, and ergonomic features.
Is user-centered design the same as usability engineering?
Not identical, but closely related and well suited to combination. Usability engineering according to IEC 62366-1 is primarily safety-oriented and requires documented evidence of risk reduction. User-centered design pursues a broader goal of safety, efficiency, and satisfaction. In practice, the iterative cycles of user-centered design deliver the formative insights that the usability engineering process requires anyway.
Why is freedom from errors in the test not enough as a goal?
Because a product that is formally tested as error-free but perceived as cumbersome or unpleasant can lead to workaround behavior in the field: Users develop their own unplanned shortcuts under time pressure. Such behavior is delicate from a regulatory perspective because it has to be reassessed as foreseeable use in the use-related risk analysis.
What is the biggest organizational hurdle for user-centered design?
Frequent access to representative users throughout the project rather than a single test cycle at the end, combined with genuine willingness to implement insights from early cycles in design changes. Without this willingness to change, only the appearance of user centering results.
Can the cycles of user-centered design be used for formative evaluation according to IEC 62366-1?
Yes, this is the usual approach in practice. In terms of content, the iterative evaluation cycles of user-centered design fulfill the formative evaluations required by IEC 62366-1, so no separate process needs to be run in parallel.
Do you want to align your product iteratively and consistently with real user needs? We integrate user-centered cycles into your usability engineering process.
More about our UX researchSources
- IEC 62366-1:2015+AMD1:2020, Medical devices, Part 1: Application of usability engineering to medical devices
- ISO 14971:2019, Medical devices, Application of risk management to medical devices
- ISO 9241-210:2019, Ergonomics of human-system interaction, Part 210: Human-centred design for interactive systems
- Regulation (EU) 2017/745 on medical devices (MDR)
- FDA Guidance: Applying Human Factors and Usability Engineering to Medical Devices