Designing Medical Devices for Safe and Effective Use

Usability Engineering, also known as Human Factors Engineering (HFE), evaluates how intended users interact with medical devices under realistic operating conditions.

Its primary objective is to identify potential use errors, reduce use-related risks, and support safe and effective device use.

The process considers user capabilities, device interfaces, clinical workflows, operating environments, and instructions for use. Integrating usability engineering into product development helps identify and address interaction problems before final design validation.

Types of Usability Studies

Exploratory and Contextual Studies

Early-stage investigations identify user needs, clinical workflows, operating conditions, and potential difficulties in device handling. Interviews, contextual inquiry, direct observation, and task analysis provide the foundation for user-centered design.

Formative Usability Evaluation

Formative studies evaluate prototypes and evolving designs to identify usability weaknesses, interaction difficulties, and potential use errors. Task-based testing, observation, and qualitative feedback support iterative design improvements.

Human Factors Validation (Summative Testing)

Human Factors Validation evaluates the final device user interface with representative intended users performing critical tasks under sufficiently realistic use conditions.

Observed use errors, close calls, and use difficulties are investigated to determine their causes and potential safety implications.Use-Related Risk Analysis and Root Cause Investigation

Usability Engineering is integrated with Hazard Analysis, Use-Related Risk Analysis (URRA), and ISO 14971 risk management.

Task-based observations and qualitative investigations identify use errors, close calls, and interaction difficulties. Root Cause Analysis examines whether these events arise from interface design, labeling, operating sequences, or environmental conditions.

Use-Related Risk Analysis connects potential use errors with hazardous situations and possible harm, supporting critical task identification, design improvements, and effective risk control.

A positive usability rating alone does not demonstrate device safety. Safety conclusions require systematic investigation of use errors, their potential consequences, and the effectiveness of risk controls.

Risk-Based Human Factors Validation

Human Factors Validation assesses whether representative intended users can perform critical tasks safely and effectively with the final device user interface.

Validation activities are based on identified use-related risks and include realistic use scenarios, structured observations, and post-task interviews.

The findings support design validation, risk management documentation, and regulatory submissions.Our Support for Medical Device Usability Engineering

We support medical device manufacturers throughout the usability engineering process, from early user needs assessment to Human Factors Validation and regulatory documentation.

Our services include:

• Usability Engineering Planning: Development of usability strategies, study plans, and risk-based evaluation approaches.
• User Needs and Task Analysis: Identification of intended users, use environments, critical tasks, and potential interaction difficulties.
• Use-Related Risk Analysis: Support with URRA, Hazard Analysis, use-error identification, and risk control measures.
• Formative Study Preparation: Definition of study objectives, test scenarios, evaluation criteria, and participant requirements.
• Human Factors Validation Planning: Development and review of validation protocols, critical task scenarios, and acceptance criteria.
• Testing Laboratory Selection: Identification and evaluation of suitable usability testing laboratories and specialized Human Factors service providers based on device characteristics, target users, testing capabilities, and regulatory requirements.
• Study Coordination: Technical coordination with external testing laboratories, including protocol alignment, test preparation, and review of study documentation.
• Results Evaluation and Design Improvement: Analysis of observed use errors, root causes, and potential safety implications to support targeted design improvements.
• Regulatory Documentation: Support with usability engineering files, risk management traceability, validation reports, and human factors documentation for regulatory submissions.

Our approach combines engineering expertise, risk-based usability evaluation, and coordination with qualified testing partners, helping manufacturers plan efficient studies, address use-related risks, and prepare reliable validation evidence.