On their journey most designers have a chance to work on a wide range of products. Some products are made for the general public, some are internal, not once used in an industrial setting. Especially in these cases a designer has to be very conscious about possible errors, as if they happen they can trigger dangerous, even life threatening situations.
When we hear the news of another unfortunate accident on the road or in a factory many times it was caused by human error. This might sound like the responsible person who was there during the given accident is to blame. Even everyday people make mistakes when interacting with products, and they might blame themselves if they cannot figure out how an application works. According to Don Norman, these accidents happen due to design problems, not the incompetence of people.
Human error is an unintentional failure in one’s actions or decisions. There are two kinds of human error, as follows:
Slips and lapses: They happen when we understand the system and the goal, choose the right actions to take, but instead we do another action which is incorrect or take no action. Slips are action-based and usually happen with things that we have a good practice in so we do them unconsciously. For example, you get distracted and try to open the front door with your car keys. Lapses are memory-based. A good example for a lapse is when you leave the dog at home while you are taking him for a walk.
Mistakes: On the other hand we talk about mistakes, when we either don’t set the right goals or the actions that we are about to take are not appropriate for the given objectives.
Besides human error a third type of human failure is violation. That is an intentional wrong action, so we are not considering it in this article.
Human-computer interaction is not always easy. The two parties have highly different traits. While machines are capable of doing repetitive tasks effectively, can store and recall large amounts of data, are quicker than humans, etc, people have limitations in attention, become distracted easily, and not to mention that the full extent of our memory is still not fully discovered. Though expectations from the human side are everything but humane. Due to our physical and mental limitations, which do not always let our interactions run smoothly, we fail many times. This is how we are, we just cannot help it. Rather, it is the beautiful task of designers to try their best to assist people to be able to avoid human error by considering our limitations.
The following points will help you to design a less error prone product, by trying to prevent them as much as possible.
Use meaningful labels: Help the users identify the items on your UI. For instance, instead of having an OK and Cancel button, you could name your OK button in a way that suggests the function that the user is going to carry out.
Give clear instructions: Supply adequate information for the users, so as to remind them - even if they already know - what to do. In addition, when they face error messages, it is really important to help them learn how to recover, e.g. think of creating a new profile in any system and trying to set your password. The best is when you get instructions about the password validity before trying to save it. If it is not there, you are expecting the system to tell you where you failed, like the password is too short, or the id does not contain a number.
Utilize warnings: Especially in danger states, like deleting something permanently, let the user know that he is about to do something that he might not want to. Let him confirm his action.
Validate input: An excellent design exercise is to prepare a perfect sign up form. One might think it is simple, but in fact it is not. There are so many things to consider and many decisions to make in every tiny part of an application. One of them is input validation. Think of how many errors one can make just on a sign up form. Please validate the input early, so users don’t run into mistakes.
Go minimal: Remove irrelevant information and unnecessary actions which just demand extra effort from the user and possibly confuse them.
Be careful with changes: Have you ever entered a one way street by a car, where the direction of the traffic has just been changed, and based on your routine you haven’t even realised it? I did. The same thing can happen on a UI, so be careful if you change something and make it clearly visible.
Offer recovery from mistakes: The best example for this is the forgiving function of “undo”. It is great when you can take back your wrong moves, learn from your mistakes and try again.
Designing for human errors might mean an extra effort for the designer, but eventually, the above steps will result in less friction and a better user experience, which is our main goal in the first place.