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HF 101: What is Human Factors?

The International Ergonomics Association (IEA) definition of human factors, also adopted by the Human Factors and Ergonomics Society (HFES) is:

Its application is now required by medical device regulators to demonstrate the safe and effective use of medical devices per guidance from the FDA as well as international standards (ISO 62366). Here’s why…

Advancements in technology have led to an increased reliance, even a dependency at times, on the equipment required to accomplish tasks. We see this in industries such as transportation, website design, healthcare and aerospace. As technology develops, its applications become accessible to a wider variety of users and skillsets. And, nowadays, technology that once was reserved for expert users is now accessible by those with or without extensive experience. Examples of this are everyday devices such as cell phones and television remotes.

Layman use of advanced technology may not be a big concern when it comes to a television remote, but it is a different story when a patient uses an at-home medical delivery device such as an autoinjector or a prefilled syringe.

We are inundated every day with design and technology experiences; whether it is something as simple as the signs telling us when we can park on a street or something more complex such interacting with surgical equipment. Take a moment and think about your individual experiences like these:

 Sorting through the apps on your smart phone

 Selecting the source of music in your car’s audio system

–  Following road signs to your destination

–  Reading the instructions for an oral medication

–  Completing an online order on eBay

As you are thinking about your experiences, also think about the environment in which those experiences occurred:

–  Waiting for a table in a noisy restaurant

–  Driving along a busy freeway

–  Standing in your well-lit bathroom

–  Sitting in your cubicle at work

…and ask yourself the following questions:

–  What did I think of the experience?

 Was I able to accomplish the task or goal I set out to complete?

–  What made the task easy or difficult to complete?

–  Was there anything that was confusing or frustrating?

–  Was I able to understand the message being conveyed by the product or sign?

–  How did the environment influence my ability to achieve my goal?

These questions may seem trivial at first, but by asking yourself, you take the first step towards objectively evaluating the technology, the provided use instructions (if any), and how the environment plays a role in completing the task. All products, signage, or labels are designed with the goal of allowing for task completion, but understanding the user experience helps us to know what makes for a good or bad design.


Why should we care that a sign, label, or product has a good or bad design?

Most everyday device interactions are relatively benign, and the worst outcome from errors would generally be user frustration. However, if these interactions are coupled with other factors, such as environmental elements like distractions and interruptions, there could be more significant ramifications (e.g., distracted driving accidents). For example, issues with your cell phone when you are sitting on your couch at home would be frustrating, but issues with cell phones while driving could lead to a fatal accident.

Errors in device interactions can be more harmful when dealing with medical devices. Distractions from environmental elements can be equally fatal, as with a car accident. But human error can also lead to life-threatening situations. One example might be that an elderly user of an autoinjector has poor eyesight and is unable to read the small print on the display. Another example is when directions are too hard to find or understand, the user could give up on the directions and just decide to make their own decision on how to use the device. Depending on the drug or device, failure to read displays or follow the directions could lead to an overdose or other injury (e.g., inappropriate injection site).


Human factors and usability testing significantly reduces the possibilities of everything from patient frustration to life-threatening consequences.

Completing usability testing throughout the design process maximizes the opportunities to identify and correct any problems within the design that may lead to use errors. If the design flaws are not addressed, the results can be harmful to both patient and pharmaceutical company:

–  Loss of user satisfaction that reduces consumer loyalty market share

–  Safety ramifications that result in user injury or death

–  Product recalls that result in additional costs and lost time at market

The combination of a human user and a machine (i.e., technology) creates a human-machine system. The human-machine system is dependent on both the effectiveness of the machine and the human’s capability to work with the machine. Overall system success depends on the success of the human-machine system within the working environment. By viewing technology and its user as single system, it becomes possible to evaluate and design the optimal way to accomplish the system goals. Human Factors also gives us the capability of designing technology and products in a way that promote efficiency and safety of the human user within expected and reasonable environments.

One of the ways of viewing the human-machine system is completing human factors usability testing. Usability testing and error identification can be done with the participation of users from target user populations. However, it can also be done without participants, when time and other product requirements require. Two non-participant methods are performing heuristic evaluations and collecting expert reviews.

The field of human factors incorporates aspects of domains, such as graphic design, psychology, and engineering, into an interdisciplinary approach in order to optimize human and system performance. Human factors considers various characteristics of the human user while evaluating a product, such as their cognitive (perception, memory, attention, etc.) and physical capabilities. Incorporating the capabilities and limitations of the human user promote effective and efficient product designs across all user populations.

The applications of Human Factors Usability Testing are wide-reaching.

Human factors usability testing can be performed to evaluate a wide array of systems across industries, such as the comprehension of medication instructions, the identification of road signs, and the usability of phone applications or website designs. When developing a new website, phone application or drug delivery system, human factors specialists can evaluate the design for both usability and accessibility throughout the design process. This allows for improved iterations of the design to be created.  The same principle applies to the design of medical devices.

From the above, you can see that there are two key reasons to become familiar with human factors:

1.   Regulators now require human factors principles be applied to the design of medical devices to demonstrate their safe and effective usability.

2.   Human factors results in the development and optimization of products that work better for customers, physicians, and patients. You should ask yourself if delaying the inclusion of human factors is worth the consequences of not delivering a better product and experience to your consumers – especially when considering the risks outlined earlier in this article.

At Suttons Creek, our human factors team has the expertise to aid you with all your human factors needs. Our team has experience with over 50 formative studies, over 20 summative studies, and all our summative work has been approved by the FDA. We will support your team at any phase of the design process to help your team receive FDA approval.

Matthew Nare, Consultant – Matthew Nare is a junior consultant on the human factors team for Suttons Creek, Inc. His previous work as a physical therapy aide provided an opportunity to gain clinical experience in inpatient and outpatient rehabilitative care settings. He came to Suttons Creek Inc. following an internship completing clinical observational research with MedStar Health’s National Center for Human Factors in Healthcare. Additionally, he spent over a year completing accessibility evaluations at Cal State Long Beach’s Center of Usability in Design and Accessibility. This combination of work experience and his educational background provides him with a unique perspective on how the medical devices and their users function.

LinkedIn: Matthew Nare


Proctor, R. W. & Van Zandt, T. (2017). Human factors in simple and complex systems, second edition (2nd ed.). CRC Press, Inc., USA.

Wachter, R. M (2012). Understanding patient safety, second edition (2nd ed.). The McGraw-Hill Companies, China.