Thanks! You've successfully subscribed to the BONEZONE®/OMTEC® Monthly eNewsletter!

Please take a moment to tell us more about yourself and help us keep unwanted emails out of your inbox.

Choose one or more mailing lists:
BONEZONE/OMTEC Monthly eNewsletter
OMTEC Conference Updates
Advertising/Sponsorship Opportunities
Exhibiting Opportunities
* Indicates a required field.

The Fundamentals of a Human Factors Program


A critical element to the integration of human factors within a manufacturer is management’s recognition that the company needs the right expertise. Human factors engineering is a discipline that, like any other, takes training and knowledge. 

“In reality, you need professional human factors engineers,” Schaffer says. “When we see operations handled in a mature way, you have professionals that are properly trained and certified. You have them working in an organization structure that integrates them into projects. They’re working against a defined methodology with specific deliverables and activities, using a set of tools and techniques that are well established in the field. We know how to do the work, but it’s another thing to see it properly applied in an organization. Very often I see organizations approach it with a lick of paint. You might get away with that on your website, but for the medical device that operates in complex ecosystems with lives at stake, it is not okay.” 

Manufacturers also fail to recognize that a successful outcome—in this case, a well-designed, intuitively-used device—requires input from several departments.

“You cannot rely on the engineering effort alone in order to pull off a sound usability/human factors engineering program,”Ngungu says. “These devices are used by nurses, doctors and even in some cases the patients. There are various disciplines, including industrial engineering and marketing folks, who know what an acceptable standard would look like. Most companies will bring in just the engineering side and not the clinical side, who know how this device is used, and no one from the marketing side, who knows how to present it.”

Design Requirements
Manufacturers struggle to choose the point during the design process wherein they should incorporate human factors. The answer is: from the start. Usability specification should be included in design input and output requirements. 

Ultimately, the foundation of any sturdy usability program relies on a thorough understanding of the way that people are actually going to use your device. To do this, manufacturers need to define the users. The questions that should be answered include: Who is the user? Who is the patient? What is the complexity of the environment in which the product is being used? What is the workflow before and after use of the product? Do you need to take into account global considerations? Can user error result in injury, or even death?

Data from prospective users and competitive intelligence needs to be incorporated in the design. “Look at all of the FDA data and the issues that similar devices have encountered, and make sure those are captured,” Ngungu says. “It doesn’t mean that you’re going to be able to hit all of them. It means that it is part of your design goal. Maybe you only get 50 percent of the way there, but it’s better than not having it in the first place. You would rather have 100 requirements that you threw in and hit 20 of them than have zero requirements and hit zero. There is value in making an attempt so that you know it was a consideration that went into the thought process.” 

As Ngungu puts it, there’s no such thing as 100 percent safe. In designing the various components of a device and its packaging, manufacturers need to define how much risk they’re willing to accept. In determining acceptance criteria, he recommends the 90 percent standard, in which 90 percent of the population of users should be able to execute each needed step without fault. Experts say that manufacturers also do not account for all of the possible risk factors and do not perform a thorough-enough risk analysis during the design process. 

Testing Requirements
FDA’s intense interest around human factors continues to focus on who will use the device, user-related risks and validation testing of the product. R&D, clinical and marketing all need to be aware of what processes need to take place for a successful regulatory approval. 


3 Documents to Read to Enhance
Your Usability Program

Regulatory bodies around the world are showing greater interest in human factors. Whether you’re a novice or an expert on the topic, it’s essential you stay up to date on the latest changes set forth by government and standard bodies. Ed Israelski, Ph.D., Convener of IEC and ISO Joint Working Groups on Usability Engineering Standards, recommends that device manufacturers familiarize themselves with these three important documents. 

1. FDA Draft Guidance: Applying Human Factors and Usability Engineering to Optimize Medical Device Design.
This document, issued in 2011 and expected to be finalized by the end of 2016, calls on manufacturers to consider more in their human factors studies, such as sample size and the introduction of a delay or learning delay period between when you train people for a usability study and when you actually test them.

“[FDA] raised the bar in terms of the strictness of the protocol and what you measure,” Israelski says. “Each observation in a usability study needs to be probed deeply. They really don’t want numerical acceptance criteria, which were reflected in the form of usability objectives. FDA wants you to use qualitative data; every observation you make in your early formative studies, and in your validation study at the end. Validation needs to be examined carefully for its implications for further design improvement and whether any residual risk that exists is acceptable. They want it to be a thorough analysis of everything you observe. They want you to probe subjectively, even when people do everything correctly.”

2. ANSI/AAMI HE 75:2009 Human Factors Engineering – Design of Medical Devices.
This extensive 500-page standard covers good design principles for medical devices, and is currently being updated.

3. IEC 62366-1 Application of
Usability Engineering to Medical Devices

This version was released in early 2015 and is the updated standard of the 2007 version, recognized worldwide.

“It’s the most current description of the process for usability engineering/human factors engineering,” Israelski says. “It is much improved; the older version was not as clear.”

According to Israelski, a second part to this standard is expected to be released in early 2016 and will provide tutorials and examples of the usability engineering process.

“[IEC 62366-2] will make IEC 62366-1 easier to use,” Israelski says. “Part two also directs that you must use IEC 62366 to produce a product that is focused on safety and clinical effectiveness, but you could also use human factors usability engineering for business purposes, to be more competitive and have a product that doesn’t get returned to you by unhappy users. Part two will give you more material to broaden the scope of your human factors work to first address safety and effectiveness, and second, to address business reasons for having good usability.”



Security code