Human Factors Glossary for Medical Devices
Human Factors Glossary for Medical Devices
Introduction
Within the field of human factors, there are a multitude of concepts to effectively assess and advise on usability of medical devices. To someone with limited experience in human factors, however, these terms could be confusing.
As with the products we consult on, confusion is the last thing that we would want anyone to experience. To shed some insight about the various concepts, and how crucial they are to the practice of human factors engineering, we've created this alphabetical glossary of key terms that are important to know for someone new to the field.
Glossary of Essential Terms
C
Critical Task
A user task which, if performed incorrectly or not performed at all, would or could cause serious harm to the patient or user (or others), where harm is defined to include compromised medical care.
See also: Task Analysis, Use Error
F
Formative Evaluation
A user interface evaluation conducted with the intent to explore user interface design strengths, weaknesses, and unanticipated use errors. Formative evaluation(s) are generally performed iteratively throughout the design and development process of a device, but prior to a Summative Evaluation, to guide user interface design as necessary.
See also: Summative Evaluation, User Interface
H
Hazard
A potential source of harm.
See also: Use Error, URRA
Human Factors Engineering (aka Usability Engineering)
The application of knowledge about human behavior, abilities, limitations, and other characteristics of medical device users to the design of medical devices including mechanical and software driven user interfaces, systems, tasks, user documentation, and user training to enhance and demonstrate safe and effective use.
See also: Usability, User Interface
K
Known Use Problems Summary
A summary of known use problems associated with medical devices on the market.
See also: Use Error, URRA
S
Summative Evaluation
A user interface evaluation conducted at the end of the user interface development with the intent to obtain objective evidence that the user interface can be used safely. A Summative Evaluation differs from a Formative Evaluation which is used to find and eliminate problems during the design and development process, rather than provide objective evidence that a final user interface design can be used safely.
See also: Formative Evaluation, User Interface
T
Task Analysis
An analysis where all tasks that occur in the use of a medical device are identified, and the order relationship between these tasks is analyzed.
See also: Critical Task, Task Ratings
Task Ratings
How participant performance of tasks during usability tests are scored:
Success (with no issues): The User was able to complete the task safely and effectively without Use Events.
Use Events: Unexpected User actions performed during normal use of a product.
Difficulty: The User was able to complete the task safely and effectively but had significant hesitation or challenges while completing the task.
Close Call: The User almost commits a user error while performing a task but recovers in time to avoid making the use error.
Unsuccessful: The User was unable to complete the task or committed a Use Error and was not able to recover.
See also: Task Analysis, Use Error
U
URRA (Use-Related Risk Analysis)
A risk analysis tool used to identify use-related hazards associated with medical product use and the measures implemented to reduce associated risks.
See also: Hazard, Use Error, Known Use Problems Summary
Usability
The characteristic of the user interface that establishes effectiveness, efficiency, ease of user learning, and user satisfaction in the intended use environment.
See also: Human Factors Engineering, User Interface
Use Environment
Actual conditions and setting in which users interact with the medical device.
See also: User, User Interface
Use Error
User action or lack of action that was different from that expected by the manufacturer and caused a result that was different from the result expected by the user, was not caused solely by device failure, and did or could result in harm.
See also: Hazard, Critical Task, Task Ratings
User
The person who interacts with (i.e., operates or handles) the device.
See also: User Group, Use Environment
User Group
The subset of users who are differentiated from other users by factors that are likely to influence their interactions with the medical device. Attributes of user groups can include age, culture, expertise.
See also: User, Use Environment
User Interface
All points of interaction between the user and the device, including all elements of the device with which the user interacts (i.e., those parts of the device that users see, hear, touch). All sources of information transmitted by the device (including packaging, labeling), training and all physical controls and display elements (including alarms and the logic of operation of each device component and of the user interface system as a whole).
See also: Formative Evaluation, Summative Evaluation, Human Factors Engineering
Next Steps in Your Human Factors Journey
Now that you're familiar with these essential terms, here are recommended next steps to deepen your understanding:
1. Practical Application
Review a medical device you're familiar with and identify its user interfaces, potential use errors, and critical tasks
Practice conducting a basic task analysis on a simple medical device
Observe healthcare professionals using medical devices to understand use environments
2. Additional Learning Resources
FDA Guidance: "Applying Human Factors and Usability Engineering to Medical Devices" (2016) - provides detailed regulatory expectations
International Standards: IEC 62366-1:2015+AMD1 (2020) - the global standard for usability engineering
AAMI HE75: Human factors engineering guidelines for medical devices
Online Courses: Consider FDA's CDRH Learn modules on human factors
3. Build Your Skills
Start with formative evaluations before attempting summative evaluations
Learn to create effective URRAs by studying published examples
Practice writing clear task instructions and observing user behavior
Join professional organizations like HFES (Human Factors and Ergonomics Society)
4. Common Pitfalls to Avoid
Don't confuse user preferences with safety-critical usability issues
Remember that formative and summative evaluations serve different purposes
Always consider the actual use environment, not just ideal conditions
Don't skip user group definition - different users have different needs
5. Connect with Experts
These concepts form the foundation of human factors in medical devices but applying them effectively requires experience and expertise. If you're working on a medical device project and need guidance on implementing these concepts, our team at ClariMed has extensive experience in:
Conducting comprehensive task analyses
Designing and executing formative and summative evaluations
Developing URRAs that satisfy regulatory requirements
Creating user-centered medical device interfaces
Contact us to discuss how we can support your human factors needs and ensure your medical device is both safe and effective for its intended users.
References
Applying Human Factors and Usability Engineering to Medical Devices. FDA Guidance Document (2016).
Medical devices Part 1: Application of usability engineering to medical devices, IEC 62366-1:2015+AMD1 (2020).
Shin, J., & Lee, H. (2023). Optimal Usability Test Procedure Generation for Medical Devices. Healthcare (Basel, Switzerland), 11(3), 296.
