Cicero once said that “To make a mistake is only human; to persist in a mistake is idiotic.” I do understand where he was coming from, but these words were pronounced in a time when we didn’t have the experience of writing wrong information in a form because of a tricky keyboard, or maybe selecting a wrong button a few times in a row while using an app because you’re not paying much attention to the task and that button just seems placed wrong.

The fact is that we have many experiences, many interactions, and therefore, many possibilities to err.

The definition of error itself is subject to discussions among many, but James Reason finds that there are two kinds of errors: slips (or lapses) and mistakes.

Mistakes are the things we make when we don’t have enough knowledge required to perform a task, such as what I do when faced with a complex task on Microsoft Excel (even though I’m not proud of it).

The slips, or lapses, as their name state, occur when we do know how to perform a certain task, but take a wrong action for an indefinite reason — may be lack of attention or external stimuli.

The good thing is that not all mistakes are bad — actually, many times they teach us something useful.

Susan M. Weinschenk on her book “100 Things Every Designer Needs to Know About People” mentions research conducted by Dimitri van der Linden and his team on how we learn to use computers and electronic devices. What they found is that we can classify errors as neutral, negative and positive.

When learning how to use an electronic device, we may come upon a neutral error, where the outcome isn’t as expected, but it also doesn’t interfere on our objective.

We can also make a negative error, in which the outcome goes against our objective or expectations, and we have a negative consequence.

But, as not everything’s bad, we can also happen to err in a positive way. This is when the mistake doesn’t lead to the expected result, however, we learn something from it, such as a functionality or path you didn’t know.

The thing with errors in apps, software, and products is that sometimes they can be displeasing, and other times fatal. It all comes down to the objective you’re trying to reach, the power you have, and the consequences it may bring. Selecting the wrong icon in your Instagram’s updated app or informing a wrong dosage in a medical infusion pump leads to two completely different outcomes, but are in essence, errors.

Errors in design

By this time, we’ve all heard the unfortunate tale of the Hawaiian missile false alarm.

After this infamous accident, it was extensively stated that its cause was bad UI, and many representations of what the screen would have looked like roamed the internet.

However, it’s been also mentioned that even though UI could have interfered in this situation, the user was actively trying to send that emergency alert, and therefore selected the “correct” option on their system — their objective was reached, but the mistake was on their intention, after all, the ballistic missile was supposed to be only a drill, but they didn’t get that.

When talking about design and error it’s easy to find examples on bad experiences, such as confusing road signs and befuddling forms — two examples that Alice Rawsthorn mentions on Hello World on troublesome design.

However, we also need to mention and focus on the human aspect of it — people make (a lot of) mistakes, and not all of them are due to a bad interface or confusing system message, sometimes people just miss it.

On the “A Taxonomy of Number Entry Error” study led by Wiseman, Cairns and Cox, it was discussed what led participants to make mistakes when entering memorized numbers — a task we’re faced with almost daily (probably by now you already know your credit card information by heart).

The results showed that the highest percentage of errors were explained by “No clear reason” — it was a slip.

Does it mean that probably it’s just the user’s fault and nothing’s wrong with my product?

Jeez, no. It only means that we have to work better, think more and be open to more possibilities and predictions.

A (not so) great example of failure led by bad design and people’s oversight was the Oscars incident. Misfortune ruled that night, in which the presenters were handed the wrong envelope (human slip), and the card’s design was so confusing that in a stressful situation, such as presenting a respected award, you just couldn’t make sense of it.

Typography — or lack of it — played a huge role that night, as did the attention required to make sure that the envelopes were correctly organized and handed.

In the end, it’s our job as developers, designers, writers and anyone involved in a product’s process to prevent these errors, and work on how users can recover from them.

We always need to wonder how a situation can go wrong, after all, to err is human.