What does a near-collision at Porto Airport in 2023 have in common with an American nuclear plant in the 1970s?

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There is nothing better than a story to prove a point. And what a story this is. On 28 March 1979, at the Three Mile Island nuclear plant in Pennsylvania, USA, a partial meltdown came close to causing a disaster on the scale of Chernobyl. It remains the worst nuclear accident in American history.

The accident began with faults in a secondary, non-nuclear system, compounded by a valve failure that allowed large quantities of coolant to escape.

The strange part of the story — and every good story has one — is that the operators made no attempt to close the valve. Nobody could understand why in the days that followed, not even President Jimmy Carter, who visited the site.

A light that told the wrong story

The investigation revealed that the valve had an indicator light on the control panel that was giving misleading information. Contrary to what operators assumed, the indicator did not show whether the valve was open or closed. It showed whether the valve was receiving power.

That was why the operators never tried to close the valve, which would have been enough to prevent the whole incident. In other words: the design of a single control almost caused a catastrophic nuclear accident.

According to Donald Norman, one of the world's leading authorities on usability and User Experience (UX) design, the control room and computer interface at that plant could hardly have been designed more confusingly had someone set out to do so deliberately.

This is a glaring example of a badly designed system producing errors that are then blamed on people, while the real cause goes unexamined: a design failure.

Who really made the mistake?

It is something we hear, see and read in the media constantly — accidents, disruptions and problems attributed to human error. One of the most recent was the incident at Porto Airport last month, when the tower cleared an aircraft to land while another was still on the runway waiting to take off. The investigation is ongoing and, for now, the incident is being put down to human error. Cases like these often conceal a significant share of responsibility on the part of whoever designed the system.

Today, whatever our profession, we are surrounded by systems that somebody designed. Very little attention is still paid to designing around people — what is known as Human-Centred Design. That lack of care means errors get pinned on users on the most superficial of readings, and users themselves feel inadequate for not knowing how to operate a system, when in fact the errors were built in by whoever designed it.

Avoiding this means involving specialists in usability and human-centred design in the conception of most of the systems we use every day, particularly digital ones.

If the systems we all deal with in the digital world are not designed for people, and with their operators in mind, problems are guaranteed. For one thing, a poorly designed system means a slow learning curve, which breeds frustration and low productivity.

Beyond that, if the information attached to a given field or action is not clearly explained, misunderstandings will produce errors — errors that lead to low productivity, or to far more serious outcomes, as in the nuclear accident, including financial loss or even risk to life.

Test before you launch

These failures originate at the design stage. Applications, websites and any other product must be conceived with designers who know how to design systems for people.

That means professionals with the right training, drawing on skills from the social sciences — anthropology, psychology, sociology — in order to identify people's real needs, frustrations and anxieties, and designers with specific training in usability and ergonomics, among other fields.

No system should be released without proper usability testing. A usability test involves putting people from the product or service's target audience in front of the system, under conditions as close to real ones as possible, and observing how easily they can use it as intended.

It is often a process that develops as the system matures, starting at a very early stage of conception, which can help reveal that many of the paths taken are not the right ones.

When the product launches, just as functional tests are run from a technical standpoint, usability testing is essential. That way, where there is a tendency towards particular user errors, there is still time to correct them. As the saying goes: prevention is better than cure.

Article originally published in Executive Digest.

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