Usability Engineering checklists

Usability Engineering File Template for Medical Devices

Usability Engineering for Medical Devices

Usability engineering plays a pivotal role in the design and development of medical devices, aiming to minimize use errors and the risks associated with them. As medical devices become increasingly complex and accessible to less skilled users, including patients themselves, intuitive and user-friendly interfaces are essential. Unlike pure technical implementation, the usability engineering process focuses on human factors, emphasizing safe and effective device operation. By integrating usability engineering with risk management, manufacturers can address potential use errors and improve patient outcomes across evolving healthcare scenarios.

This guide provides a usability engineering file template, a step-by-step usability engineering file sample, and a practical checklist covering what IEC 62366-1 expects a manufacturer to document.

Usability Engineering File Template

A consistent template keeps the file organized the way reviewers and auditors expect to see it: use specification, user interface specification, hazard-related use scenarios, user interface evaluation planning, formative evaluation, summative evaluation, and the final usability validation conclusion. Building the file section by section, with a clear document for each requirement, means nothing gets lost between early design work and the final submission package, and it gives every team member a defined place to add evidence as the device develops.

What Is a Usability Engineering File?

A Usability Engineering File (UEF) is the compiled record of all usability engineering activities performed during the development of a medical device. It brings together the use specification, the user interface specification, the hazard and risk analysis tied to use, the formative testing conducted during design, and the final summative validation testing conducted on the finished device.

The file exists to show two things:

• That the manufacturer systematically identified how the device could be used incorrectly, and what harm could result
• That the manufacturer designed, tested, and validated the user interface to reduce those risks to an acceptable level

This process is complemented by checklists that focus on the steps and requirements of usability engineering, and on the documents that must exist to support each step, ensuring a structured and comprehensive approach.

Usability Engineering File Requirements

A compliant UEF should demonstrate the following, consistent with IEC 62366-1 and FDA human factors expectations:

• A documented use specification covering the medical indication, patient population, body part, use environment, user profile, and operating principle
• A documented user interface specification, including technical requirements tied to the use specification
• Identification of use errors based on user interface characteristics and the use specification
• Identification of known or foreseeable hazards and hazardous situations, supported by risk analysis
• Identification and description of hazard-related use scenarios, including critical tasks
• A user interface evaluation plan covering both formative and summative testing
• Formative evaluation reports showing iterative design improvement
• A summative evaluation plan and report confirming the final interface supports safe use
• For legacy devices, a User Interface of Unknown Provenance (UOUP) assessment
• Evaluation of residual risk at the conclusion of testing

Usability Engineering File Contents

Use Specification

The use specification is the foundation document for the whole file. It should define:

• Intended medical indication
• Intended patient population
• Intended part of the body
• Intended use environment
• Intended user profile
• Operating principle

Everything downstream, from hazard identification through validation testing, is built on what is defined here.

User Interface Specification

Once the use specification is in place, manufacturers identify user interface characteristics related to safety and perform risk analysis:

• Identify user interface characteristics related to the safety of the device, and perform risk analysis on them
• Identify use errors based on those user interface characteristics and the use specification

This section should also establish a user interface specification covering technical requirements tied to the use specification, such as display color and character size, along with accompanying documentation and any device-specific training required.

Hazard-Related Use Scenarios

With user interface characteristics identified, the file should document known or foreseeable hazards and hazardous situations:

• Identify known or upcoming hazards that could affect users of the device
• Perform risk analysis based on the hazards identified
• Consider hazards from similar types of medical devices, where available

From there, identify and describe the hazard-related use scenarios associated with those hazards:

• Include all tasks and the severity of the associated harm
• Select hazard-related use scenarios for summative evaluation
• Include critical tasks based on the severity of potential harm

User Interface Evaluation

Before testing begins, establish a user interface evaluation plan:

• Identify the method of planned formative and summative evaluation
• Document the user groups to be included in testing
• Document the test environment based on the use specification
• Specify the accompanying documentation provided during testing
• Specify whether training is provided before testing

For legacy devices where the original design history is incomplete, this section also covers the User Interface of Unknown Provenance (UOUP) assessment:

• Establish the use specification
• Review post-production information
• Ensure hazards and hazardous situations related to usability have been identified and documented
• Verify and document adequate risk control
• Evaluate the residual risk

This stage is also where the User Related Risk Analysis (URRA) is performed, which is similar to standard risk analysis but focused specifically on use:

• Task analysis
• Potential user error
• Potential hazard or hazardous situation
• Potential harm
• Severity of potential harm
• Risk control measures

Formative Evaluation

Formative evaluation is the iterative testing conducted during design to find and fix usability problems before the interface is finalized.

Formative evaluation plan:

• Include the evaluation methods being used
• Identify the part of the user interface being evaluated
• Include when each user interface evaluation will be performed

Formative evaluation report:

• Maintain the user needs or requirements document, updated based on testing results

Summative Evaluation

Summative evaluation is the final validation testing performed on the finished device.

Summative evaluation plan:

• Include the evaluation method being used and its rationale
• Confirm which part of the user interface is being evaluated
• Include the criteria for determining whether safety information is understandable
• Confirm that accompanying documentation is available
• For usability testing, include participant characteristics, how participants are grouped, the test environment and conditions, the definition of correct use, and the method of collecting data during testing

Summative evaluation report:

• Maintain a summative evaluation report based on the testing conducted
• Perform summative evaluation on the final or production-equivalent user interface
• Perform testing in the actual, or a realistically simulated, use environment
• Use at least 15 users per distinct user group where required for FDA submission
• Evaluate any residual risks identified

Usability Validation

The final step ties everything together: confirming, from the summative evaluation results, that the device's user interface supports safe and effective use by the intended users, for the intended uses, in the intended environments, and that any residual use-related risk is acceptable. This conclusion is what regulators and auditors look for at the end of the usability engineering file.

Usability Engineering File Sample

A representative usability engineering file sample is organized around three main document groups, each feeding the next:

Working from a sample structured this way lets a usability or regulatory team quickly see which documents already exist and which still need to be created for a specific device.

How to Prepare a Usability Engineering File

1. Start with the use specification. Define the intended medical indication, patient population, body part, use environment, user profile, and operating principle before anything else.
2. Define the user interface specification. Capture the technical requirements, such as display characteristics, accompanying documentation, and training needs.
3. Identify use errors tied to the interface. Work through each user interface characteristic to find where errors could occur.
4. Run the hazard and risk analysis. Identify known and foreseeable hazards, referencing similar devices where relevant, and complete the User Related Risk Analysis (URRA).
5. Describe hazard-related use scenarios. Capture every task and the severity of harm it could cause, then select the critical tasks for summative testing.
6. Write the user interface evaluation plan. Decide on formative and summative methods, user groups, test environment, and documentation needs up front.
7. Conduct formative evaluation. Test early and often, documenting the method, the part of the interface tested, and the resulting design changes.
8. Conduct summative evaluation. Test the final design with representative users, at least 15 per user group where an FDA submission is planned, in a realistic environment.
9. Evaluate residual risk. Review the summative results against the risk analysis to confirm remaining risk is acceptable.
10. Compile the usability engineering file. Bring every document together in one traceable file, referencing the use specification through to the summative evaluation report.
11. For legacy devices, complete the UOUP assessment. Where the original design history is unavailable, use the User Interface of Unknown Provenance pathway instead of recreating missing records.

Usability Engineering File Checklist

• Use specification prepared, covering medical indication, patient population, body part, use environment, user profile, and operating principle
• User interface characteristics identified and linked to safety-related risk analysis
• Use errors identified based on user interface characteristics and the use specification
• Known or foreseeable hazards and hazardous situations identified
• Risk analysis performed based on identified hazards
• Hazards from similar medical devices considered, where available
• Hazard-related use scenarios identified and described, including tasks and severity of harm
• Critical tasks selected for summative evaluation based on severity
• User interface specification established, including technical requirements and accompanying documentation
• Device-specific training requirements documented, if applicable
• User interface evaluation plan established, covering methods, user groups, test environment, and documentation
• User Interface of Unknown Provenance (UOUP) assessment completed, for legacy devices
• User Related Risk Analysis (URRA) completed, including task analysis, potential user error, hazard, harm, severity, and risk controls
• Formative evaluation plan prepared, identifying methods, interface parts, and timing
• Formative evaluation report completed, with updated user needs documentation
• Summative evaluation plan prepared, including method, rationale, and criteria for understandability
• Participant characteristics, grouping, test environment, and data collection method defined for summative testing
• Summative evaluation report completed on the final or production-equivalent interface
• Summative testing performed in the actual (or realistically simulated) use environment
• At least 15 users per distinct user group included, where required for FDA submission
• Residual risks evaluated and documented
• Usability validation conclusion documented, confirming safe and effective use

FAQs About Usability Engineering File Templates

What is a Usability Engineering File (UEF)?
A UEF is the compiled record of all usability engineering activities for a medical device, including the use specification, user interface specification, hazard and risk analysis, formative testing, and summative validation testing. It demonstrates that the device's user interface supports safe and effective use.

What should a usability engineering file template include?
At minimum, it should cover the use specification, user interface specification, hazard-related use scenarios, the user interface evaluation plan, formative evaluation, summative evaluation, and a usability validation conclusion.

How is a usability engineering file sample organized?
A typical sample groups documents into planning (use specification and user interface specification), risk and scenario identification (hazard analysis and URRA), evaluation planning, formative testing, summative testing, and a final validation conclusion.

What is the difference between formative and summative evaluation?
Formative evaluation is iterative testing performed during design to find and fix usability problems before the interface is finalized. Summative evaluation is the final validation testing performed on the finished, production-equivalent interface to confirm safe and effective use.

How many participants are needed for summative evaluation?
At least 15 users per distinct user group are generally expected where the evaluation is intended to support an FDA submission, though the right number ultimately depends on the device and its user groups.

What is a User Related Risk Analysis (URRA)?
A URRA is similar to a standard risk analysis but focused specifically on use. It covers task analysis, potential user error, potential hazard or hazardous situation, potential harm, severity of harm, and the risk control measures applied.

What is User Interface of Unknown Provenance (UOUP)?
UOUP applies to legacy devices whose original usability engineering documentation is incomplete or unavailable. Instead of recreating the full process, manufacturers establish the use specification, review post-production information, confirm usability hazards have been identified and documented, verify risk controls, and evaluate residual risk.

Does the usability engineering file need to be updated after the device is validated?
Yes. If the user interface, labelling, or use environment changes, the relevant sections of the file, including hazard analysis and evaluation testing, should be revisited to confirm the conclusions still hold.

Is the usability engineering file the same as a human factors report?
They overlap significantly. The usability engineering file is the complete internal record of the process under IEC 62366-1, while a human factors report is often the summarized version of that file prepared specifically for a regulatory marketing submission.