GP-025 Usability and Human Factors Engineering

Procedure flowchart

Purpose

This procedure ensures that the design and development team appropriately applies human factors and usability engineering processes, enhancing safety and effectiveness for intended users, uses, and environments. The purpose of including human factors engineering information is to demonstrate that the device's user interface is appropriate for the intended users, uses, and use environments.

Scope

This procedure covers the usability engineering (human factors engineering) processes applied throughout the lifecycle of software medical devices, focusing specifically on user interfaces and all user interactions. It includes device commissioning, installation, operation, maintenance, repair, and disposal.

References

Reference document code	Reference document description
ISO 13485:2016	Medical devices - Quality management systems - Requirements for regulatory purposes
EN ISO 13485/A11:2021	European standard for medical devices quality management systems
21 CFR 820.30	FDA regulation for design controls in medical devices
Regulation (EU) 2017/745	Regulation of the European Parliament and Council on medical devices
IEC 62366-1:2015	Application of usability engineering to medical devices
IEC 62366-2:2016	Guidance on usability engineering for medical devices
ISO 14971:2019	Medical devices - Application of risk management
ISO 24971:2020	Guidance on risk management for medical devices
FDA Guidance (2016 & 2022 drafts)	FDA guidance documents on human factors and usability engineering for medical devices

Definitions

• Abnormal use: Conscious, intentional act or intentional omission of an act that is counter to or violates normal use and is also beyond any further reasonable means of user interface-related risk control by the manufacturer.
• Correct use: Normal use without use error.
• 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, where harm is defined to include compromised medical care.
• Formative evaluation: User interface evaluation conducted with the intent to explore user interface design strengths, weaknesses, and unanticipated use errors.
• Hazard-related use scenario: Use scenario that could lead to a hazardous situation or harm.
• Normal use: Operation, including routine inspection and adjustments by any user, and stand-by, according to the instructions for use or in accordance with generally accepted practice for those medical devices provided without instructions for use.
• Summative evaluation: 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.
• Task: One or more user interactions with a medical device to achieve a desired result.
• Use error: User action or lack of user action while using the medical device that leads to a different result than that intended by the manufacturer or expected by the user.
• Use scenario: Specific sequence of tasks performed by a specific user in a specific use environment and any resulting response of the medical device.
• Usability engineering (or Human factors engineering): Application of knowledge about human behavior, abilities, limitations, and other characteristics to the design of medical devices (including software), systems, and tasks to achieve adequate usability.

Responsibilities

JD-001

• To approve the entire process of the products according to the initial requirements.

JD-005

• To ensure that the entire process of control, verification and validation of the products design and development is carried out according to the methodology established in the present procedure.

JD-003

• To oversee and coordinate the entire design and development process of the products in accordance with the methodology outlined in this procedure.

JD-004

• To ensure that the design and development procedure is performed following this procedure, and that all the records required are properly generated, reviewed, approved and archived accordingly.

Relationship between FDA and IEC 62366-1:2020

When conducting usability engineering for medical devices, we follow the requirements of both FDA guidance document Applying Human Factors and Usability Engineering to Medical Devices and the IEC 62366 standard. We will, however, follow the structure of IEC 62366 when naming the sections of the usability engineering file.

The following table summarizes the relationship between the FDA guidance document sections and the corresponding clauses in IEC 62366-1:2020, along with the relevant records that we maintain to demonstrate compliance with these requirements.

ID	FDA Guidance Document Section	IEC 62366-1:2020 Clause	Placement in our documentation
1	Conclusion - Brief summary of HFE/UE processes and results that support this conclusion - Discussion of residual use-related risk	5.9 Perform a summative evaluation	T-TF-025-007 Summative Evaluation Report
2	Descriptions of intended device users, uses, use environments, and training - Intended user population(s) and meaningful differences in capabilities between multiple user populations that could affect user interactions with the device - Intended use and operational contexts of use - Use environments and conditions that could affect user interactions with the device - Training intended for users	5.1 Prepare Use Specification	Description and specifications, section "Intended Use"
3	Description of device user interface - Graphical representation of device and its user interface - Description of device user interface - Device labeling - Overview of operational sequence of device and expected user interactions with user interface	5.6 Establish User Interface Specification	SF14.03_Software Requirement Specification
4	Summary of known use problems - Known use problems with previous models of the subject device - Known use problems with similar devices, predicate devices or devices with similar user interface elements - Design modifications implemented in response to post-market use error problems	N/A	T-TF-025-007 Summative Evaluation Report
5	Analysis of hazards and risks associated with use of the device - Potential use errors - Potential harm and severity of harm that could result from each use error - Risk management measures implemented to eliminate or reduce the risk - Evidence of effectiveness of each risk management measure	5.2 Identify user interface characteristics related to safety and potential use errors 5.3 Identify known or foreseeable hazards and hazardous situations 5.4 Identify and describe hazard-related use scenarios	R-TF-025-002 Identification of characteristics for safety, possible use errors and hazard-related scenarios
6	Summary of preliminary analyses and evaluations - Evaluation methods used - Key results and design modifications implemented in response - Key findings that informed the human factors validation test protocol	5.7.2 Formative Evaluation Planning 5.8 Perform user interface design, implementation and formative evaluation	T-TF-025-003 User Interface Evaluation Plan GP-012 Design, redesign and development
7	Description and categorization of critical tasks - Process used to identify critical tasks - List and descriptions of critical tasks - Categorization of critical tasks by severity of potential harm - Descriptions of use scenarios that include critical tasks	5.3 Identify known or foreseeable hazards and hazardous situations	R-TF-025-002 Identification of characteristics for safety, possible use errors and hazard-related scenarios
8	Details of human factors validation testing - Rationale for test type selected (i.e., simulated use, actual use or clinical study) - Test environment and conditions of use - Number and type of test participants - Training provided to test participants and how it corresponded to real-world training levels - Critical tasks and use scenarios included in testing - Definition of successful performance of each test task - Description of data to be collected and methods for documenting observations and interview responses - Test results: Observations of task performance and occurrences of use errors, close calls, and use problems - Test results: Feedback from questionnaires or interviews with test participants regarding device use, critical tasks, use errors, and problems (as applicable) - Description and analysis of all use errors and difficulties that could cause harm, root causes of the problems, and implications for additional risk elimination or reduction	5.5 Select the hazard-related use scenarios for summative evaluation 5.7.3 Summative evaluation planning 5.9 Perform summative evaluation of the usability of the user interface	R-TF-025-001 Usability plan T-TF-025-003 User Interface Evaluation Plan T-TF-025-004 Summative Evaluation Protocol

Input Data

Collected before or early in design and development from:

• Clinical and validation studies
• User feedback
• Similar devices
• Regulatory standards

Detailed Process

Use specification

Identifies users, environments, medical indications, and operational principles.

Identification of characteristics related to safety and possible use errors

The user interface characteristics that could be related to safety need to be identified. These characteristics can be related to the operating principle of the medical device, its intended use, and/or the reasonably foreseeable misuse.

Considering these characteristics and the use specification, possible use errors are then identified. Task analysis techniques can be used to study how users would interact with the user interface by defining a succession of tasks and sub-tasks. Potential use errors can then be identified for each of the tasks by taking into account the perceptual inputs, cognitive processing, and physical actions of the user involved in performing the task.

These use errors will be then analyzed in the next step to identify the potential consequences of the errors and the potential resulting harm.

Identification of known or foreseeable hazards and hazardous situations

Considering the use specification, data from comparable devices (predicates), and identified use errors, the known or foreseeable hazards, and hazardous situations related to the medical device are identified.

This identification is conducted as part of a risk analysis performed according to the ISO 14971 risk management process and SOP06_Risk management, and therefore these elements are documented in the risk analysis file folder in the usability section.

The following flowchart has been extracted from Figure A.5 – The relationship between the RISK MANAGEMENT PROCESS (ISO 14971:2019) and the USABILITY ENGINEERING PROCESS (IEC 62366-1) of the IEC 62366-1:2020 standard. It illustrates the relationship between the usability engineering process and the risk management process, highlighting how they interact and inform each other throughout the design and development of medical devices.

Identification and Description of hazard-related Use Scenarios

These elements are documented in the risk analysis file folder since the hazards, the sequence of events, and the harms resulting from human factors are identified there.

Selection of hazard-related Scenarios for Summative Evaluation

Choose scenarios based on risk severity.

User Interface Specification

Detailed requirements, testing parameters, and mitigation strategies.

Evaluation Plan

Detail the formative and summative evaluations, including methodology and documentation.

Formative Evaluation

Ongoing evaluation integrated into design and development activities.

Summative Evaluation

Final validation conducted with end-users to demonstrate risk mitigation effectiveness.

Documentation

Templates

• T-TF-025-001 Usability plan
• T-TF-025-002 Identification of characteristics for safety and possible use errors
• T-TF-025-003 User Interface evaluation plan
• T-TF-025-004 Summative evaluation protocol
• T-TF-025-005 Summative evaluation observation form
• T-TF-025-006 Summative evaluation questionnaire
• T-TF-025-007 Summative evaluation report

Associated Procedures

• GP-012 Design, Redesign and Development
• GP-013 Risk Management

Signature meaning

The signatures for the approval process of this document can be found in the verified commits at the repository for the QMS. As a reference, the team members who are expected to participate in this document and their roles in the approval process, as defined in Annex I Responsibility Matrix of the GP-001, are:

• Author: Team members involved
• Reviewer: JD-003, JD-004
• Approver: JD-001