Usability is a way to measure how easy a product is to use. It is a concept in design circles to ensure products—whether websites, furniture, or hotel lobbies—can be used as simply and painlessly as possible.
For example, imagine you’re a UX designer or UX researcher building a website for a kitchenware company. Can users easily find and browse product offerings, despite never having visited the site before? Can they easily adjust items in their cart if they add something accidentally? Do customers come away from the website feeling satisfied, or confused and frustrated? These are some of the questions you’ll address by thinking about usability.
Jakob Nielsen, co-founder of leading user experience (UX) design firm Nielsen Norman Group and pioneer of usability, outlines five components that define good usability:
Learnability: A user should be able to learn to carry out simple tasks the first time they use a product.
Efficiency: Users should be able to complete tasks quickly once they’ve grasped the basic design of the product.
Memorability: Even if users don’t use a product for a period of time, they should be able to come back and remember how to use it.
Errors: A user should make few severe errors, and a product should allow users to recover from them.
Satisfaction: Using a product should be a pleasant experience.
If usability is the ease of using something, utility is its actual usefulness. Utility asks of a product: can you accomplish the task you set out to do in the first place? Even if an app to make haircutting appointments is easy to use and delightful to navigate (hallmarks of good usability), there’s no point in using it if you can’t actually make appointments.
Usability and utility are in turn both distinct parts of the user experience (or UX). UX encompasses the entire process of a user interacting with a product. Depending on the definition, UX can also include desirability, brand experience, credibility, accessibility, and findability.
Good usability means users can accomplish their tasks quickly, with minimal stress and errors, and ultimately feel satisfied in their interaction with a product. For companies creating products, this becomes important for attracting customers. Users are more likely to gravitate toward products with better usability, and more likely to recommend those products to other people.
For websites in particular, usability is crucial. Visitors to a website can easily leave as soon as they encounter difficulty or confusion. When you buy a physical product, you have to go to the store or post office to return it. With a website, it’s much easier to navigate away from a less-than-ideal product.
Designers, user researchers, and usability specialists often run products through a process called usability testing, which can help determine what expectations, preferences, and troubles a user has. Once they have a clearer idea of what's going well—and what isn't—they can refine a design.
It's important to conduct usability tests throughout the design process, so you can identify any potential issues as early as possible. Usability testing takes several different forms. These include:
Card sorting: Write out concepts (like features) on notecards, and ask participants to organize them into groups that make sense, then create labels for those groups. Card sorting is useful in thinking about how to organize a website or mobile app, and is often used in the mockup or wireframing stage.
Guerilla testing: A team brings a design or prototype into a public space like a cafe or park, and passersby are asked for their input. This can be a quick, low-cost way to gather feedback.
Session recordings: Often used with digital products like websites or apps, session recordings entail a researcher watching a recorded session of a user navigating the product to accomplish a task. This can also include a heatmap analysis—a visual representation of where most users are clicking, scrolling to, or pointing their mouse.
Lab usability testing: Participants are invited into a controlled environment where a moderator can observe their behavior or ask questions as they interact with a product. Since lab tests require significant coordination, and participant numbers are usually limited to small groups, lab testing is good for in-depth, qualitative research.
Remote usability testing: Participants complete a series of tasks at home. Remote usability testing can be monitored or unmonitored: If it's monitored, a user researcher is likely "watching" the participant use the product in real-time via a shared virtual space, whereas if it's unmonitored, the participant will record their session for a researcher to review later.
Determining which is the best usability test for your product depends on your budget, scheduling, and time constraints. Remote testing tends to be less expensive than in-person testing, but in-person testing can reveal a wealth of helpful information thanks to a user's body language, facial expressions, and more.
Read more: What is a UX Researcher? How to Get the Job
Usability tests will ideally reveal a lot about how your product can be improved. If you’re keeping an eye out for metrics on how to improve usability, consider the following metrics:
Success rate: Whether users can complete a task at all
Time: How long it takes for users to complete a task
Error rate: How many errors users made
Satisfaction: How satisfied users were
Tip: Before you begin designing a new product or redesigning an older product, it's important to conduct pre-design research. Spend time researching and defining 1) who your users are, 2) what the central design problem is, and 3) what the design requirements are.
Being able to implement usability principles into a creation process has the potential to make a product easier, more intuitive, and more satisfactory to use. There are several routes you can take to start learning about usability and usability testing.
Not sure where to start? In the Google UX Design Professional Certificate, you’ll learn the basics of UX research and testing, and plan your own UX research study. You can also dig deeper into the usability test process through the University of Michigan’s User Experience Research and Design Specialization.
A Guided Project, offered on Coursera, allows you to practice UX design. With the iPhone Application Flow with Wireframes in Miro, you'll learn how to apply UX principles and design an iPhone app flow.
Usability is a useful concept to learn for most any type of designer or user researcher—UX designers, product designers, UX researchers, and otherwise. Usability can also be helpful to understand for product managers, UX engineers, UX writers, and other players involved in the creation process of a product.
In addition to the five components of usability, Jakob Nielsen defined the ten usability heuristics. The usability heuristics are considered rules of thumb for designers who want to create intuitive products.
The 10 heuristics are:
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