5 min read
2 FEB 2021
We live in a world in which human-computer interactions occur very often in many different ways. In principle, users interact with desktop computers, mobiles, or wearables to achieve some predefined goals. Therefore, factors that enable users to use these devices in a desirable way (i.e., operating systems, applications, or websites) must be usable. One of the ways to ensure that digital products are usable is heuristic evaluation. In this article we will explain what the 10 usability heuristics for human-computer interaction are.
According to one of the pioneers of usability engineering, Jakob Nielsen: "Heuristic evaluation is done by looking at an interface and trying to come up with an opinion about what is good and bad about the interface" (Nielsen, 1993, 155). To provide the effectiveness of evaluation, in 1994, Nielsen released a set of 10 general principles that help individual evaluators make their assessment. What’s important is that they are broad rules of thumb rather than formal norms.
When users interact with a digital system, they should know what is going on in a specific moment. A good example of this can be a progress indicator in the e-commerce website during the purchase of a product or a battery life icon in an operating system. This evokes a sense of trust in the user.
According to the second heuristic, a system should speak a users' language and follow real-world conventions. Let’s assume that we want to design a call-to-action button that allows users to submit the problem that has occurred when using the mobile app. It is better to name this button "Submit a problem" instead of "Report a bug." The language that is understandable for the developers might be confusing for the users. The basket icon in the e-commerce website is the appropriate example real-world conventions. In most cases, when people go shopping in a neighborhood shop, they put products into the basket.
When interacting with a system, users make some mistakes, just like in real life. Unfortunately, during real-world interaction between two people, it is impossible to "undo" spoken words. It might cause frustration and conviction about the lack of control of the action taken. In digital systems, you can just take the "emergency exit" through an "undo" action or a "cancel" button. Thanks to them, users feel freedom and full control over what they do.
The fourth heuristic includes internal and external consistency. Internal consistency refers to a single product or family of products. If we decide that actionable elements (i.e., call to action buttons) have a green color across the website, we shouldn't use it for static elements like a header. External consistency is related to some broadly established conventions in the industry that we should follow. On most websites, the logo is placed on the top-left corner in the navigation bar, so we shouldn't set a logo on the right side. If we break this rule, we may cause “cognitive load”. Or to put it in simple words, we may go beyond the maximum amount of information that can be comprehended at once.
Preventing errors is crucial for good product usability. Users often make mistakes by accident. The results might be serious, like, for instance, sending an email to many recipients instead of one or removing essential data. Therefore, usable design should prevent these kind of accidents by means of warning messages or action confirmation.
According to the sixth heuristic, design shouldn't force users to recall crucial elements on the interface. It is better to provide some clues that help users to recognize them. A good example of that are labels that describe the fields on a form. When users provide data into fields, labels should still be visible. If labels disappear, users have to recall what information a specific field requires, so their cognitive effort increases.
A system is efficient and flexible when it provides options or actions that speed up interaction. These can be keyboard shortcuts, touch gestures, or a quick access menu. They are called accelerators. Thanks to them, a system can be efficient for experts and friendly for novice users.
The eighth heuristic could also be called: "Communicate, don't decorate." A well-designed interface shouldn't have elements that are irrelevant or rarely needed. Each graphic element in the system should aid users in achieving their goals. Thanks to it, users are focused on their main actions and aren't distracted by unnecessary information.
Errors always have occured and will occur in digital products. A system should inform users of what has happened clearly and understandably without technical jargon. When users identify a problem, it is good to provide them some potential actions to solve it. When we follow this heuristic, users will not feel fear or uncertainty.
Even when assume that our product is easy to use, we should never take it for granted that our users think the same way. Therefore it is good to provide them with help documentation. That will help them achieve their tasks faster and more efficiently.
Heuristic evaluation can be beneficial for products in an early stage of development and existing ones. In the first case, heuristic evaluation can be conducted instead of usability tests that require much more engagement. However, it is good to use both of these methodologies to ensure the highest usability of a product. In the second case, heuristic evaluation can be helpful for UX audit. Although Jakob Nielsen's 10 usability heuristics were released in 1994, they are still valid and will likely apply in the future.
Nielsen, Jakob. 1993. Usability engineering. Boston: Academic Press.
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