Why You Can’t Ignore Usability Engineering

A medical device should ideally serve its intended purpose in a pretty straightforward way. People do not wish to spend much of their time trying to figure out how to use the device or worse, use one that do not really serve its purpose. This is why usability engineering is becoming more important over the years and definitely playing a big role now in the medical device industry.

What is Usability Engineering?

Usability engineering is the process of identifying potential hazardous situations with user-device interactions and exploring ways to mitigate it. It focuses on the creation and improvement of user interfaces that keep the eventual medical device easy, effective and safe for use.

Both IEC 62366-1:2015 and FDA HF/UE guidance details the importance of usability engineering. As referenced in the guidance, usability has become part of the pre-market approval process at the U.S. FDA. This states how much emphasis the U.S. FDA has placed on usability engineering. Elsewhere, most people uses the IEC 62366-1 standard as it is widely accepted in most countries and is also FDA-CDRH recognised.


Why Is Usability Engineering Important?


Poor usability engineering of medical devices has proven to be one of the highest risks for compromising patient safety. When usability considerations are lacking, users face difficulties in handling the device. Confusion set in, leading to device misuse, mishandling and can result in poor treatment outcome. From a medical device product owner’s point of view, all of these points towards poor customer experience, increased customer complaints and expensive re-design of device. 

Usability ensures that user errors and misuse are minimised. Additionally, user-friendly products tend to be more popular and could give your organisation the competitive edge.


Is Usability Engineering Different from Risk Management?

Risk management (ISO 14971) is the systematic approach towards the application of procedures and policies to identify and mitigate potential hazards. We would recommend approaching usability engineering as part of the risk management processes – considering how the users interact with the medical device throughout the entire process and mitigating any identified risks as part of the risk management exercise.


When Should You Start Thinking About Usability Engineering?

design control waterfall diagram

All design teams should look into usability engineering as early as they have identified the intended use and user needs of the device. Once these are done, the team can more or less identify the potential hazards that may occur throughout this entire user/patient-device interaction. These are key information for the team so they can include design features that can mitigate these risks early in the design phases (design inputs). Of course, these new design features may also adversely introduce further usability issues and should be re-evaluated through the risk management exercise.

Once the design outputs (device specifications, manuals, labels, packaging and etc) are finalised, usability considerations are often verified and validated with functional tests, simulated tests and usability trials to demonstrate safe and effective use of device. These could also be performed as part of a clinical trial, depending on the preference of the organisation.

It’s never too early to think about usability. Let’s take a look at stepwise on how can this be done!


How To Implement Usability Engineering

risk acceptability matrix
  1. Specify the application (intended use) of the medical device first, including user profiles, use environment and use scenarios, intended patient population and etc. 
  2. Identify hazards related to potential use errors and hazard-related scenarios – the same way as how risk management is conducted. Proposed a risk level for each hazards based on probability and severity.
  3. Implement risk controls – establishing user interface specifications (design inputs in design control).
  4. Design user interface (Design Output).
  5. Evaluate design with the team and early adopters/stakeholders with the intent to identify design’s strength, weakness and any unrecognised use errors.
  6. Review comment and modify design to improve on the user interface. This iterative cycle can continue until the design can be locked down.
  7. Verify and validate risk controls through a series of tests that includes simulated tests and having the actual users trying them out.  The purpose is to obtain objective evidence that usability-related hazards and issues are addressed.  
  8. Identify residual risk based on the revised probability and severity.
  9. Continue to monitor and update the risk management file accordingly throughout the entire lifecycle of your device.  



In the latest ISO 13485:2016, usability is included as part of design inputs requirements. Usability engineering ensures ease of use and safety of use of medical device. It is not a separate process and should be implemented throughout your medical device development and risk management!

Interested to setup and implement a QMS for your company, or require us to evaluate your regulatory strategy for your medical device? Contact us now for more information, including a 30-minute complementary gap analysis to understand what's needed for you to get or stay compliant!

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