Imagine your friend has moved to a new city and you’re planning to visit. You’ve never been there before and aren’t sure what to expect from the weather, which makes packing difficult. You send a quick text to your friend asking how the weather has been lately and in response, your friend sends back an Excel spreadsheet full of numbers.
Does this help you decide what clothes to pack? Probably not.
You would need to know quite a bit about those numbers for them to help you solve your packing dilemma: Do these numbers reflect humidity? The average temperature? Or perhaps the chance of rain?
Your friend sent raw data, which has the potential to inform your choices, but doesn’t quite do the trick on its own [1]. This example illustrates the difference between raw data and information; raw data lacks usefulness without context and interpretation.
What does this have to do with medical devices?
For the most part, medical devices are used by people who did not design them. This means that users must somehow learn what a device does and how to operate it, which requires designers and manufacturers to communicate with users about the device’s functions, capabilities, and limitations.
This communication occurs in a variety of places, perhaps most obviously, the instructions for use (commonly called the IFU). The IFU is a document provided with medical devices that includes detailed information on how to correctly use, operate, and maintain the device. IFUs can be long, highly detailed, and may contain information that is useful to some people and irrelevant to others.
Presenting information in a way that is understandable to all user groups, without overwhelming them, is a key challenge.
Information anxiety & The five hat racks
More is not always better when it comes to information. Richard Saul Wurman coined the term “information anxiety” to describe the stress and confusion that arises when people are overwhelmed by the volume of information they encounter and struggle to make sense of it [2].
Wurman proposed that information anxiety can be mitigated when information is organized in a way that enhances clarity and usability. The five hat racks is a structured approach to information organization that can guide designers when they communicate with the users of their devices.
So, what are the five hat racks?
In the table below, we define the five hat racks and give examples of how we can use each to organize different types of information in a medical device IFU.
*Note: The original label of this hat rack was Continuum but was changed to Hierarchy in a later edition of the book, so we have presented both here [3].
Why do hat racks help?
Let’s take a step back and think through the metaphor. You have a closet full of hats that needs to be organized. Where would you start?
You may prefer to organize your hats based on season (e.g., winter hats vs. summer hats) while I may choose to organize my hats by color. Who is right?
To understand the best way to organize the hats, we need to know something about the context in which people are wearing them. Perhaps I primarily use hats as a fashion accessory, so organizing by color guides my selection process. If your hat wearing is primarily functional, to keep warm in the winter and cool in the summer, organizing hats by season better reflects your needs.
Similarly, to organize information effectively, designers need to consider their users characteristics (e.g., literacy level), needs, and priorities. For more on designing clear and usable IFU, check out some of our other blogs!
- Human Factors of Effective Warning Statements
- Making Instruction Manuals Usable – Human Factors and UX
- Human Factors and FDA: Instructions for Use (IFU)
TLDR;
People who use medical devices need to somehow figure out what devices can do, and how to make them do it. Informing users of these capabilities often requires communicating a large amount of information, some of which might be highly detailed or technical.
Wurman’s concept of “information anxiety” illustrates the challenges people face when presented with poorly structured information. By using the Five Hat Racks—Location, Alphabet, Time, Category, and Hierarchy/Continuum—designers can reduce confusion in their communication with device users.
Sources
- Information anxiety: Towards understanding. Available at: https://www.wurman.com/publishedarticles/2017/5/5/information-anxiety-towards-understanding (Accessed: 13 August 2024).
- Wurman, R. S. (1989). Information anxiety. Doubleday.
- Lidwell, W., Butler, J., & Holden, K. (2010). Universal principles of design. Rockport Publishers.
For more resources on Medical Device Human Factors please check out our blog and YouTube channel.
