Edged Out

In product design, particularly software design, there’s something referred to as an edge case. Originally, the term referred to a product experiencing an unanticipated use at the maximum of its operating parameters. Edge case doesn’t refer to a product being used for something it shouldn’t (the classic using a screwdriver as a prybar comes to mind), rather a product being used for what it was designed to do, but under conditions that weren’t anticipated by the designers. Unfortunately, edge case is often a term used to narrow product design to a very homogeneous set of “average” users.

In my household, we recently purchased a new vehicle, replacing our over ten year old car. In the years since we bought our old car, Advanced Driver Assistance Systems (ADASes) have become much more standard in vehicles. ADASes are safety systems which do things like warn of hazards that may cause a collision and might even apply the vehicle breaks in an emergency. Our new vehicle came equipped with this kind of system, and we soon became used to its insistent warnings that the threshold of our garage was putting us in imminent danger, or that I was getting way too close to the pile of snow at the end of our turnaround.

According to the American Automobile Association (AAA), an issue with ADASes is that they are often tested under ideal conditions. This means that your vehicle’s safety systems may never have encountered snow, rain, ice, or bug death on your windshield. The problem with ADASes in adverse conditions is that their censors can stop “seeing” the road and fail to prevent the very same collisions they might prevent in ideal conditions. This limited testing means that for almost half the year, you may effectively be an edge case as far as this system’s design is concerned.

Edge cases aren’t supposed to describe people, according to designer Michael Wilson. However, edge cases certainly affect people. And when a product’s target audience is large, such as anyone driving a modern vehicle, even a small percentage of edge cases adds up to a very large number. We found ourselves in those unanticipated conditions when driving to Toronto in some very wintery weather. With the car caked in icy slush and no easy way en route to turn off the widgets that were now doing their best impression of HAL 9000, it made an already strenuous drive even more harrowing. Organizations like AAA recommend against relying on ADASes in inclement weather, especially in the winter.

Other examples of edge cases have very large sets of users who have to suffer through them. An app not working because of poor internet connectivity? Welcome to rural Ontario among many other places where people live and don’t have great internet. AI voice assistants that are only trained in English in a specific American accent? Sorry the rest of the entire world.

Edge cases become especially problematic when they are used to justify a design that further marginalizes an already marginalized group. As an example, censors for handsfree operation of faucets and soap dispensers are notorious for not working well for people who have darker skin. Voice assistants not understanding women’s voices as well as men’s is another. Capacitive touch screens being more difficult for older people to use because aging skin has a harder time retaining moisture (which is needed for a touch screen to work) is yet another.

Better products come from designing for the widest variety of people and circumstances as possible. OXO Good Grips, the kitchen utensil company, was originally started when founder Sam Farber noticed his wife was having difficulty gripping kitchen tools due to arthritis. The brand is often a favourite of reviewers such as America’s Test Kitchen and The Wirecutter. OXO Good Grips even details how they design and test their products “beyond ‘normal’ consumer use” on their blog. They have built a business model on not just designing for the average user, and they’ve created well regarded and sought after products as a result.

Often, in the rush to implement a new technology, designers forget to stop and ask who they are designing for. Rather, the desire is to quickly make something that works well for a simplified definition of “the average user” under ideal conditions in order to get a product out the door. Too often this “average user” looks a lot like the peers of the designers themselves, statistically that trends heavily toward white, male, and urban. This means that great swaths of users simply never have products that are designed for them and their circumstances. As designer Mike Monteiro said in Ruined by Design, “When you decide who you’re designing for, you’re making an implicit statement about who you’re not designing for.”

Learn more

Rain Dropped: AAA Says Driver Assist Systems Can Fail In Poor Weather. 2021. Jim Gorzelany. (Forbes) Last accessed 2024/08/18.

In Bad Weather, Advanced Vehicles May Not “See” the Road. American Automobile Association. Last accessed 2024/08/18.

Capacitive controls could be the cause of a spate of VW ID.4 crashes. 2024. Jonathan M. Gitlin. (ArsTechnica) Last accessed 2024/08/18.

When driver assistance becomes driver distraction. 2024. Steve Vaughn. (Fleet Owner) Last accessed 2024/08/18.

Don’t Call Us Edge Cases – Designing From the Margins. 2022. Afsaneh Rigot. (Harvard) Last accessed 2024/08/18.

Why do we dismiss certain user types as “edge cases”? 2020. Denis Boudreau. (Medium) Last accessed 2024/08/18.

People are never edge cases. 2023. Michael Wilson. (Medium) Last accessed 2024/08/18.

What is an edge case? Meaning, examples in software development. 2023. Shehab Beram. (LogRocket) Last accessed 2024/08/18.

Everything everywhere all at once: designing for edge case. 2023. Yung-Ching Chiu. (YouTube) Last accessed 2024/08/18.

Hey Siri! Do you understand me? 2019. University of Johannesburg. Last accessed 2024/08/18.

Hey Siri—Why Don’t You Understand More People Like Me? 2021. Sinduja Rangarajan. (Mother Jones) Last accessed 2024/08/18.

Voice Recognition Still Has Significant Race and Gender Biases. 2019. Joan Palmiter Bajorek. (Harvard Business Review) Last accessed 2024/08/18.

Touch screens don't work for everyone. 2021. Gabe Fender. (Gabe's Design Blog) Last accessed 2024/08/18.

OXO (kitchen utensils brand). Wikipedia. Last accessed 2024/08/18.

Behind the Design of the OXO POP Containers. 2019. OXO Blog. Last accessed 2024/08/18.

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