About That Edge Case

Inspired by Douglas Crockford

Photo by 𝓴𝓘𝓡𝓚 𝕝𝔸𝕀 on Unsplash

Douglas Crockford is one of the luminaries of the Javascript world. His most famous work, Javascript: The Good Parts, helps developers avoid some of the nasty bits of the hastily created language and adopt smart patterns given its idiosyncrasies.

I was watching him speak recently and he stopped me in my tracks with this line:

‘That hardly ever happens’ is another way of saying, ‘it happens.’

For years as a product manager, I’d hear frequently, and use myself, the refrain that some feature or another was an ‘edge or corner case’. Both of these terms have their own technical definitions, but for our purposes, we can treat them as equivalent — either one denoting something outside ‘normal’ operating conditions.

Usually proclaiming something an ‘edge case’ is a feature killer — relegating the idea to the backlog we speak not of. If I’m honest, when I’ve made these statements, it’s been an outright dismissal of the idea. I didn’t believe in the approach, found it confusing, or perhaps considered it ‘too expensive’ — so I filed it under ‘edge case’, disposing of it expeditiously. In light of Crockford’s statement, I wondered if this habit might be an error of hubris. Product Manager slang that sounded supremely smart, but instead made for worse products.

Maybe instead of handing the steering wheel to our emotional bias reflexively, we should consider how we might serve the ‘rare issue’ elegantly, without extra cognitive cost to the user? If this out of bounds situation happens now and then (instead of never), maybe it’s worth exploring?

Jason Fried has a productive heuristic on interface design. He calls it Obvious, Easy and Possible. In adding any feature, he asks himself how prominent it should be in the interface. The important actions should be obvious, the once in a while, easy, and the infrequent, but still important, possible.

“And finally are the things that are possible. These are things people do sometimes. Rarely, even. So they don’t need to be front and center, but they need to be possible.”- Jason Fried

Taking Uber as an example, we would say that hailing a ride is obvious, messaging your driver is easy, and updating your credit card is possible. How about the Nest thermostat? Adjusting the temperature to 72˚ is obvious, setting your home to ‘away’ is easy, but viewing your wiring set-up, while rarely needed, is possible. Not impossible, possible.

We already know the edge case is outside the expected day to day use, that’s not news. The salient question is if the infrequent should be supported. A glance through your iPhone settings provides myriad examples of rare, but important abilities. Even infrequently used features can be essential to the experience.

As builders, don’t dismiss the rare need out of hand. In these moments, we have work to do! Our job just might be finding a way to support this infrequent, but important action, without compromising the other, more important areas of the interface. Even if, in the end, you decide to dispatch with the feature, you’ll have learned a bit more about your product intuition and one day, your customers will thank you for it.

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Paul Pedrazzi

Paul Pedrazzi

Product @ Salesforce. Advisor @flipboard. Subscribe: pedrazzi.substack.com