Human factors engineering (HFE) is the systematic application of knowledge about human capabilities, limitations and behavior to the design of products, systems and work environments. In medical technology, HFE pursues the same goal as the usability engineering process according to IEC 62366-1: to enable safe and effective use and to reduce use errors to an acceptable level.
Subject matter and objective
Human factors engineering starts from a basic assumption that has long been consensus in safety-critical industries: Human behavior is not an unpredictable disturbance variable but is largely predictable. Under certain conditions, people systematically overlook information, confuse similar elements according to recognizable patterns, and their performance declines under time pressure, fatigue and distraction in a describable way.
From this follows the central change of perspective in HFE: A use error is not primarily a failure of the user but an indication of a design that did not adequately take human characteristics into account. Thought through consistently, this means: If an error is foreseeable, it can also be designed against, and its prevention therefore lies within the manufacturer's responsibility.
HFE considers all three stages of human information processing equally: perception, processing and decision, and action execution, the perception-cognition-action model. This completeness distinguishes HFE from a purely design-oriented or purely ergonomic view.
HFE and usability engineering: two terms, one process
The variety of terms in this field has historical and geographical reasons, not reasons of content. The FDA consistently uses “human factors engineering”, while European standardization speaks of “usability engineering” in IEC 62366-1. Both describe the same systematic process with the same core steps and largely congruent requirements.
For manufacturers seeking approval in both markets this is a practical relief: A consistently managed process can satisfy both sets of rules. The differences lie less in substance than in terminology, documentation format and individual expectations, for example regarding participant numbers in human factors validation testing or the design of the final report, which is expected in the US context as an HFE/UE report. In relation to ergonomics, HFE acts as its applied branch: Ergonomics provides the scientific foundation, and HFE translates it into design decisions for a specific product. Outside medical technology, “human factors and ergonomics” (as used by the IEA and HFES, for example) denotes the whole discipline, including physical ergonomics; in this wiki, HFE refers to the medical device context.
Components of an HFE program
A complete HFE program follows a continuous chain in which each step builds on the previous one:
- Use specification: Intended purpose (intended use), user groups with user profiles and use environment as the starting point.
- Context and workflow analysis: Empirical collection of the real conditions of use instead of assumed ones.
- Task analysis: Breaking use down into action steps and deriving use scenarios.
- Use-related risk analysis: Identification of possible use errors, their consequences and the critical tasks.
- Design and risk control: Implementation in the user interface, labeling, accompanying materials and, where applicable, training.
- Formative evaluations: Iterative testing during development, analytical and empirical.
- Summative evaluation: Provides objective evidence on the final product with representative users.
- Documentation: Traceable consolidation in the usability engineering file.
What matters is the continuity of this chain. The most frequent shortcoming in practice is not a missing individual step but a broken link: analyses that do not lead to any design decision, or tasks in the summative evaluation that cannot be traced back to the documented critical tasks. A central feature of a robust HFE process is therefore traceability between use specification, task analysis, use-related risk analysis, critical tasks, design decisions and evaluation results. For the US market, the FDA describes with human factors validation testing a closely related, separately defined format of evidence. The goal of the entire process is ultimately the derivation and assessment of effective use-related risk control measures.
The scope of the user interface
A regularly underestimated point: The user interface in the sense of usability engineering comprises far more than the display. It includes all points of contact through which a user interacts with the product: controls and displays as well as labeling, packaging, instructions for use and training materials.
This has direct consequences for risk control. According to the established hierarchy of risk management, prevention is first by inherently safe design, then by protective measures in the product, and only lastly by information for safety. A warning in the instructions for use is thus the weakest permissible measure, not the most obvious one. Where a use error can be prevented by a design change, the warning is not an equivalent substitute.
Why HFE has to start early
The cost of a design change rises steeply over the course of development. An operating concept can be changed with little effort in the concept phase; fixing the same problem after the design is complete affects tooling, verification, labeling and documentation.
The most unfavorable point in time is the one at which findings experience shows to occur most frequently: in the summative evaluation. If a critical use error is observed there, the consequence is not only a design change but, as a rule, also a repeated summative evaluation, with a corresponding effect on approval date and budget. Early formative evaluations are therefore not additional effort but the most effective safeguard against precisely this scenario.
Regulatory reference
The FDA human factors guidance describes HFE as an expected component of product development. Which documentation has to be submitted has been described since 2026 by the guidance “Content of Human Factors Information in Medical Device Marketing Submissions” through three human factors submission categories (see HFE/UE report). In Europe, the process that corresponds in content is governed by IEC 62366-1, supplemented by the application guidance in IEC 62366-2.
The EU Medical Device Regulation (MDR) requires in Annex I that risks associated with use errors be reduced, taking into account the ergonomic features of the product as well as the knowledge, experience and training of the intended users. Through the use-related risk analysis, HFE is closely interlinked with risk management according to ISO 14971; for the Chinese market, comparable requirements exist with the NMPA usability guidance.
Human factors engineering translates established knowledge about human capabilities and limitations into concrete design decisions and treats foreseeable use errors as a design task, not as a failure of the user. In content it largely coincides with usability engineering according to IEC 62366-1; the terms separate regulatory traditions, not procedures.
The value arises from continuity and early use: Analyses must lead to design decisions, and these must be in place before a change becomes expensive.
Frequently asked questions (FAQ)
Is human factors engineering required only for high-risk products?
No. The scope and depth of the HFE process depend on the risk and complexity of the product. Taking use-related risks into account is, however, relevant for all medical devices.
Is HFE the same as a usability test?
No. Usability tests are only one component of the HFE process. Human factors engineering comprises analysis, risk assessment, design, evaluation and documentation across the entire development cycle.
Is human factors engineering the same as usability engineering?
In content, largely yes. The terms come from different regulatory traditions (the FDA speaks of human factors engineering, IEC 62366-1 of usability engineering) and describe the same systematic process. The differences lie in terminology, documentation format and individual expectations, not in substance.
Are the instructions for use part of the user interface?
Yes. The user interface comprises all points of contact between user and product: besides controls and displays also labeling, packaging, instructions for use and training materials. Accordingly, these components must also be included in analysis and evaluation.
Are warnings and training sufficient as a risk measure?
As a rule, no. The hierarchy of risk control provides first for inherently safe design, then for protective measures in the product and only lastly for information for safety. A warning is thus the weakest permissible measure and no substitute for a design solution where one is possible.
When should HFE begin in the development process?
With the intended purpose and the use specification, that is, before the first design decisions. The later HFE starts, the more expensive changes become. The most unfavorable case is a critical finding in the summative evaluation because, besides the design change, it usually also entails a repetition of the evaluation.
Do you want to integrate human factors engineering into your development process from the start, up to the summative evaluation? We implement the process with you in a structured and standards-compliant way.
More about our usability engineeringSources
- IEC 62366-1:2015+AMD1:2020, Medical devices, Part 1: Application of usability engineering to medical devices
- IEC/TR 62366-2:2016, Medical devices, Part 2: Guidance on the application of usability engineering to medical devices
- ISO 14971:2019, Medical devices, Application of risk management to medical devices
- Regulation (EU) 2017/745 on medical devices (MDR)
- FDA Guidance: Applying Human Factors and Usability Engineering to Medical Devices
- FDA Guidance: Content of Human Factors Information in Medical Device Marketing Submissions