Best practices

Questions answered here

• Why does human factors prioritise severity over probability for use errors?Human factors prioritises severity over probability because reliable data on use errors is rarely available. Complaints underreport use errors, and simulated studies lack the sample size for meaningful probability calculations. Consequently, low probability cannot justify accepting a use error risk, meaning potential harm severity must drive risk mitigation decisions.
• What does human factors maturity look like in medical device development?Human factors maturity means integrating user needs, risk reviews, design decisions, formative research, and post-market data across all development phases to improve safety. Rather than treating validation as a regulatory checklist hurdle before submission, mature organisations embed this mindset from the beginning, making regulatory evidence a natural outcome of good design.
• Why is mitigating medical device risks through the IFU considered weak?Mitigating use-related risks in the IFU shifts the burden onto users rather than resolving design flaws. Under IEC 62366, information for safety requires evidence that users perceive, understand, and follow instructions under pressure. Because users frequently miss or misinterpret text, relying on manuals leaves manufacturers exposed to potential use errors.
• Why is understanding user behaviour crucial in medical device human factors?Human factors engineering requires understanding why users interact with a device in specific ways, especially when distracted, tired, or under pressure. Rather than simply documenting errors or task completion, identifying the behavioural causes behind use-related risks enables teams to design out risks and prevent safety problems before validation testing.
• What is the hierarchy of risk control measures for medical devices?Under ISO 14971 and IEC 62366, the risk control hierarchy prioritises design changes, followed by protective measures, and lastly information for safety. Engineering out risks eliminates hazards directly. Protective measures reduce risk but leave hazards present, whilst information like warnings and instructions is the weakest control because it relies entirely on user behaviour.
• Why should medical device teams not rely solely on simulated usability testing?Relying solely on simulated usability testing means discovering usability problems too late, when design changes are difficult to justify. Applying varied IEC 62366 human factors methods earlier allows teams to understand users, workflows, environments, tasks, and risks beforehand. Selecting the appropriate method at each development stage prevents waiting until validation to address user struggles.
• Why does leading language slip into human factors usability scripts?Leading language frequently appears in human factors summative protocols because everyday conversational habits naturally contain subtle bias. Practitioners unintentionally transfer these speaking patterns into testing scripts without realising it. Addressing this issue requires actively recognising these linguistic habits, which can be achieved by studying common logical fallacies to prevent biasing participants during testing.
• Why should user physical capabilities be considered early in medical device design?Medical device design must incorporate users' physical capabilities, such as force limits, vision, hearing, and component manipulation, especially for home-use products. Designing based solely on technical aspects risks failing user needs. Understanding these realistic physical constraints upfront ensures usability actively drives design choices rather than merely justifying decisions after the fact.