Expert tips on human factors engineering for medical devices from a human factors specialist.

June 19, 2015

5 Min Read
Human Factors Engineering: 8 Simple Rules

Expert tips on human factors engineering for medical devices from a human factors specialist.

Gareth Walker

Owen Mumford’s state of the art test lab analyses its prototypes to ensure new innovations perform as expected.

The term “human factors engineering” is widely recognized across the medical industry. Simply put, it is about designing for people. When designing medical devices, it is easy to focus on optimizing the physical components of a system, but human factors engineering ensures that the end-user—whether this be the patient using the device in every day life, or a healthcare professional in a clinical environment—is considered in the early design stages.

By understanding the intended users, a product can offer the appropriate capability and also be as easy as possible to use, allowing benefits such as improved self-management. When working to address healthcare needs, getting this early stage of design and human factors engineering right is essential.

There are many processes behind successful human factors engineering—here are some expert tips for the journey from Gareth Walker, human factors specialist at Owen Mumford.

1.Critical Areas of Process

First, identifying the critical areas of process is essential to forward planning. You need to consider Application Specification, Risk Evaluation, User Evaluation, and Validation Testing—Summative Study.


With any project, time and time management is always highly important. When designing medical devices, it is critical to ensure you plan for change. Design iterations will always occur, so ensuring you have allowed enough time to work these in is vital.

If you plan ahead, you will avoid the time delays associated with reworks and the necessary approvals required. Changes are far easier to make during development than to incorporate them retrospectively.


As with time, if you identify any issues or required changes to a device early on, solutions can be designed in before they become prohibitively expensive. Refining designs through early study and iteration can be done more easily and with less expense than a full-scale summative study.

Commonly cited wisdom from Software engineering: a practitioner’s approach by Roger S. Pressman states that the cost of fixing a usability problem for a product during the design process is multiplied by 10 once it is developed and multiplied by 100 once it is for sale.


A diagram showing the processes within human factors engineering

4.Application Specification

This is a key document that is always best to get completed early. Knowing how a system will be used helps identify aspects that will have an influence on the design itself. It will also identify what gap you are trying to fill in the market with your device, giving a destination for the whole development process.

With this, knowing your audience is crucial. Identify all the users, including anyone who interacts with the device in its life (think about distribution and disposal too). It’s easy to overlook people but those users may have the most problems.

During this specification, you will also identify which factors will have the biggest impact on the use of the system, and therefore the design (depending on the purpose of the system). These factors include physical capabilities, cognitive capabilities, and factors specific to the medical condition.

5.Risk Assessment

There are three key aspects, which are important to consider during Risk Assessment. You should take every opportunity to remove opportunities for error from the design:  

  • Leverage the Task Analysis as much as possible—you should identify the user steps and foreseeable user errors at the concept stage, allowing errors to be designed out.  

  • Incorporate the Risk Assessment into the design process—don’t let risk mitigation be an afterthought. It can’t all be done with training and the instructions for use.

  • Mitigate risks proactively through design—prevent errors by removing the opportunity, rather than just telling people not to do it.

6.Formative Study

Don’t confuse formative studies with market research—both have value but they are not the same thing. Market research gives you an understanding of where a product will fit in the market, but formative studies make sure it can be used when it gets there.

Formative studies give you the opportunity to explore issues, expand ideas, evaluate opportunities, and prototype the device.

7.Summative Study

First, it’s important to understand the purpose of the summative study. You need to prove that the device can be used safely and effectively.

Understanding what the results of this study will mean, before starting the study, is critical. How will you prove that the intended users, in the correct environment, can use the device safely and effectively? What will negative results mean?

Where training is integral to the use of a system, participants must be trained in a way that matches how they would be trained in the real world. The study also has to show that the device is safe when used by an untrained user, this way it shows what would happen in the worst-case situation.

8.Human Factors Summary Report

This report must summarize all the human factors related activity on a project from start to finish. It must show clear consideration of human factors throughout project development with the summative study providing the majority of that evidence.

It’s vital this becomes a standalone document to facilitate review—don’t make the reviewer flit between multiple documents to understand the situation as this may distract them from the message you are trying to convey. Be clear and show consideration of all important user risks and document how they were addressed.

Considering human factors early in the design cycle not only leads to safer, more effective products, it can also speed time to market and reduce costs. The number one rule to take away from all of this is to use all the knowledge and information at your disposal to create a device that truly considers the end user, helping to aid them in the management of their condition.

Enhance your medtech knowledge by attending MEDevice San Diego, September 1–2, 2015, in San Diego.

Gareth Walker is a human factors specialist at Owen Mumford, a medical device developer and manufacturer.

[Image courtesy of Owen Mumford Ltd.]

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