FDA guidance and international standards for human factors emphasize the importance of conducting a robust validation, or summative, study before a device goes to market. The guidance and standards clearly state that a validation study must evaluate whether the device can be used safely and effectively by intended users, in intended use environments, and for intended uses.
One of the most crucial elements in any usability study is participant recruitment. Ensuring you have the right participants who accurately represent your target user population is essential for generating meaningful and regulatory-ready data. However, recruiting representative participants can be a complex and nuanced process, often involving logistical hurdles, strict inclusion criteria, and potential access limitations.
That’s where Kaleidoscope Innovation comes in. Our team can help you navigate the challenges of participant recruitment, offering expert support and strategic guidance to ensure your study includes the right users and meets regulatory expectations.
"The most important consideration for test participants in human factors validation testing is that they represent the population of intended users." – FDA, 2016 (Ref. 1)
“A usability test calls for a sample of representative users to interact with a given medical device.” – IEC 62366-1:2015 (Ref. 2)
What is Representativeness?
Representativeness can be defined as, “serving as a typical or characteristic example of a particular group of people or of a particular thing.” In a validation study, representative means the participants should reflect the range of end users who will operate the device in the real world. This includes not just their professional roles, such as nurses or physicians, but also relevant characteristics such as age, physical or cognitive abilities, and levels of experience or training.
Why You Should Care
Medical errors can happen when devices are not intuitive or forgiving of user mistakes, especially under stress. A validation study aims to uncover these risks by testing the device in simulated, but realistic, conditions. If the participants do not adequately reflect the intended user population, the study can miss critical usability issues. For example, a device that is easy for a tech-savvy nurse to use may confuse an elderly caregiver at home. If a representative of that caregiver isn’t included in the validation study, designers might not discover the problem until after the device is already in the users’ hands. And finally, failing to include representative users can delay regulatory acceptance or approval, and potentially lead to the need for additional studies.
Getting it Right in Your Study
Recruiting a representative sample often takes more effort and planning than it might initially seem. It requires thinking beyond who is most accessible and making sure to include people who may be harder to recruit but are essential to evaluating real-world use.
Engaging users early, such as through formative research or with assistance from a design research team, the exact user characteristics necessary for device use can be successfully identified. These characteristics might include users with vision or dexterity limitations, individuals with limited technological experience, or those with lower health literacy. By emphasizing a proactive approach for ensuring participant representativeness, the likelihood of costly design changes later in development is reduced, safety risks are minimized, and there will be an increased likelihood that the final product will be intuitive, efficient, and safe to use. likelihood that the final product will be intuitive, efficient, and safe to use.
Human factors validation studies are about identifying and mitigating risk, not just ticking a regulatory box. Ensuring the participants recruited are truly representative of your device’s user population is a cornerstone of a successful study. Skipping this step risks both regulatory rejection and patient safety.
References
- S. Food and Drug Administration. (2016, February 3). Applying human factors and usability engineering to medical devices: Guidance for industry and Food and Drug Administration staff.
- International Electrotechnical Commission. (2015). IEC 62366-1:2015 Medical devices – Part 1: Application of usability engineering to medical devices.
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