The U.S. Food and Drug Administration (FDA) describes human factors engineering as “The application of knowledge about human behavior, abilities, limitations, and other characteristics of medical device users to the design of medical devices including mechanical and software driven user interfaces, systems, tasks, user documentation, and user training to enhance and demonstrate safe and effective use. Human Factors Engineering and Usability Engineering can be considered to be synonymous.”
I view human factors engineering (HFE) as being an essential part of User Experience Design (UXD) and a major component of ensuring that human well‐being and system performance are optimized through three main categories:
These methodologies aid in assessing behaviors, abilities, limitations and other characteristics. The difference between these methodologies should be clearly defined. Team members outside of the field will request a usability test when research or evaluation may be more appropriate. Be sure you understand their product question before committing to a specific methodology.
The main objectives of HFE are:
Notice that safety is listed as the first objective. Many people believe that the main focus of a human factors engineer is usability. While this is true in consumer products, in medical, the priority is safety. Take the example of a power button. Often times, the power button on a medical device will be placed in the back, in a lower harder to reach corner, which is clearly not user-friendly. The reason for this is to avoid accidental shut down. Even when a power button is on the front of a device, there is typically a requirement to press and hold the button for 3 seconds in order to avoid accidental powering off.
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A good HFE process should be:
1. Ongoing: The process is not a one‐time test that finds all design flaws.
2. Measurable: The process should include metrics, defined and observable so that improvements to your product and ROI are measurable.
3. Iterative: Testing and designing involves repetition in order to refine the design and usability.
4. Integrated: The HFE process should be integrated into product development. It is the key to ensuring you are making data-driven design decisions throughout the development life cycle.
Assuming you have established an HFE process that includes the items above, how do you go from a checklist of items to complete a robust process? The word “robust” is thrown around a lot but nailing down a definition of what this means can be difficult. It’s a buzzword that feels abstract. To tighten the definition and concept here are a few items to consider:
For example, at one company I worked for, my task was to start an HFE division. Over a period of five months, I was able to get involved with the product development process training offered to all functions throughout the company. Over that five-month period, I presented to 513 individuals spanning the U.K., the U.S. and Singapore. Individuals included in this training came from a variety of functional areas such as marketing, customer support, electrical engineering, mechanical engineering, Program Managers and Core Team Leads. What this meant for me – every time a new project would arise, someone from one of these functions would contact me to request support from my team.
Collaboration with multifunctional groups is critical to the success of HFE being accepted and understood as a valuable part of the company skill sets.
Strong documentation. Some of the most important information in history is in the form of a document. Historical documentation comes in many forms, cave paintings, stone carvings, maps and diaries. Documentation takes time – and in some cases, you may view it as wasted effort because you may think no one will take the time to read it anyway. Before you jump to this assumption, consider the items that should be documented in HFE activities.
All of this information is important and can feed into any of the following:
Templates used to document this information as well as increase the robustness of your process and include the following:
Consistent documentation is required – I often hear the phrase, “If it’s not documented, it didn’t happen.” This is absolutely true, especially when it comes to design traceability, the design history file and a submission to the FDA for 510k of premarket approvals (PMA).
All of these functions help keep tasks on track, teams aligned and expectations clear. Each of these documents may come at different points in the product development process. I have seen the most success in delivering at these stages:
Stage 0 Opportunity Generation: Exploratory Research/User Research Plans and reports.
Stage 1 Concept Definition: HFE Project Plans: Now that you have an understanding of pain points and user needs from the research conducted in stage 0, what are your overall project plans for HFE activities?
Stage 2 Feasibility: Known Use Errors – What do we know is wrong, and how can we fix it?
Stage 3 Design and Development: Use related Hazards Analysis‐ identify mitigations and begin testing them in formative usability tests. After several iterations and once a production equivalent system is ready, create an HFE Validation Test Plan, execute the test and finalize the report.
Stage 4 Launch Preparation: Complete the HFE Engineering Project report. Summarize all activities, identify any deviations from the plan written in Stage 1 and ensure everything in in your project Design History File.
Stage 5 Full Market Release: Conduct postmarket surveillance to ensure safety and usability issues are being tracked and fixed.
HFE processes provide maximum benefit when integrated into the existing product development process as a parallel activity along with other product development functions. Ideally, HFE is applied throughout the development process, starting with concept development activities. However, even if a project is in later stages, it’s better to include analysis at that time, rather than not at all.
At worst, releasing a product without due consideration for HFE could lead to the injury or death of a patient or health care professional. At best, poor attention to HFE could drive business away to competitors, which hurts a company's bottom line.
HFE provides a better user experience and increased ease of use, so even if your organization isn’t a medical device company – it’s good for business.
Tressa Daniels is the Associate Director of User Experience Design and Human Factors Engineering at Becton Dickinson in San Diego. She has worked in the field of HFE for 21 years. Daniels’ expertise is in user interaction design, ethnographic research and executing human factors analyses of consumer and medical products, including infusion pumps, oral medication dispensing systems, migraine machines and DNA Sequencers. Formerly, she worked at Illumina, CareFusion, HP, Intel and Xerox and was a HF instructor at Woodbury University in Burbank, Calif., and is also a member of AAMI Faculty in Human Factors in Medical Device Design. Daniels is a member of the Human Factors and Ergonomics Society (HFES) as well as the Association for the Advancement of Medical Instrumentation (AAMI). She serves on AAMI’s Human Factors Engineering Standards Committee as well as hosts regular webinars for AAMI. Daniels holds a bachelor’s degree in psychology as well as a master’s degree in human factors engineering and applied experimental psychology. She can be reached at email@example.com.