Design Error
I’m in the doghouse. Mrs Lawther asked me to do the washing whilst she was out. As I am a modern man and expect to do my bit, I was happy to comply with the request. Unfortunately, there was a complication. The washing included my wife’s very chic and expensive dress. Ordinarily, this is a hand-wash-only item, but Mrs Lawther assured me that putting it in with everything else in a “30oC Mixed Load” wash would be fine. It went into the washing machine with underwear, shirts, and my daughter’s school uniform.
Two hours later, whilst I was relaxing and reading a book, my wife emptied the washing machine (I was only asked to switch it on). I received robust and frankly unfair feedback about needing to look at the b####y dial whilst setting the machine. She also asked me — maybe instructed — to buy her a new dress. I had washed everything at 90oC.
I professed my innocence. Only an idiot would set the machine at 90oC when instructed to run a cool wash, but when I looked at the dial, it became uncomfortably clear that I had made a mistake. The 90oC setting was only one notch up from the “30oC Mixed Load” point.
The Accident That Was Bound to Happen
Sooner or later, some fool would make the mistake. Unfortunately, I was the fool. Some other fool with the same washing machine will undoubtedly repeat the error.
But here is the question:
Who is the bigger idiot? The husband or the designer? If the selector moved progressively from cold to hot, instead of making 60oC leaps, I’d have only washed the scarf at 40oC, and nobody would have been the wiser.
Design errors are lurking accidents. Some call them latent human errors. They are mistakes waiting to happen.
Design Error is Rife
Have you ever:
- Pulled on a door handle, only to find it was a push door?
- Sworn at an overly complicated phone app that will not do what you want?
- Ignored a PowerPoint Slide because it contained too much information?
It is easy to blame humans for errors, but if you want them to stop, a fresh human isn’t the solution, though better-designed products, software, and processes might be.
Design Out the Errors
In his book, The Design of Everyday Things, Don Norman (director of The Design Lab at the University of California) explains the principles of good design. They are as relevant to business processes and systems as to consumer goods. Some of my favourites include:
Be Clear and Simple
Less is more, as it removes the number of ways things can go wrong or be misinterpreted. Take away the knobs and dials and adjusters (or data and reports), so only the information and actions that are necessary remain. Apple, Google and Amazon are masters of simplicity.
Provide Visual Cues
If your business process design must be complicated, add visual cues that make it obvious to customers and staff what they need to do next. The Schiphol Fly is an excellent example of a visual cue.
Error Proof the Design
If people can’t do the wrong thing, performance can only improve. There are plenty of ways to make it easy for people to do the right thing instead.
Give Real-Time Feedback and Validation
Provide feedback so that people know if what they are doing is working or not. Rumble strips on the side of a road are great for warning a driver of impending doom. The feedback is instant. However, the delay between adjusting a thermostat and the temperature changing in a room can lead to wild fluctuations.
The faster you can provide feedback, the less likely people will over-adjust.
Think About Context and Mental Models
Our experiences have conditioned us to look at the world a certain way. Red is bad, green is good. Clockwise tightens, anticlockwise loosens. ABC, accelerator break and clutch. Building on existing conventions makes it easier for people to understand how things work.
If your design is novel or counterintuitive, don’t be surprised when people do what they think is right instead of what you want.
Create a Clear Hierarchy
If you provide information for people, make sure the important things are clear and bold, and the supporting information is smaller and less likely to attract the wrong sort of attention.
The Three Mile Island nuclear incident could have been prevented by moving the dials on the control panel, and the Oscar debacle wouldn’t have happened if somebody had changed the font sizes on the award cards.
Reduce Cognitive Load
Error messages are great, but what should you fix first if you are presented with hundreds of them? Boeing redesigned the feedback given to pilots of their planes so that only the most pressing issues are presented rather than overwhelming them with information.
Incorporate Safety Measures
Error proofing stops things from going wrong, but nobody gets hurt if a design is fail-safe and things go awry.
- A three-pin plug error-proofs the electricity supply.
- A fuse board ensures it fails safely.
Test Your Design
Once you have created the “perfect design”, test it with real-life employees and customers. What may be blindingly obvious to you won’t be as clear to them.
If You Only Do One Thing
You can’t eliminate design errors but can minimise them by creating a culture where people highlight and fix problems. Encourage your staff to be open about problems and issues rather than sweeping them under the carpet for fear of the consequences. Nothing will ever improve if everybody is busy jumping up and down, pointing the finger at human error.
Unfortunately, this is easier said than done. In a fit of generosity, I offered to buy a new washing machine instead of a new dress. My wife suggested an alternative course of action.
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Photo by Oli Woodman on Unsplash
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