1 Establishing the essentials
Communication equals remembering what it’s like not to know.
—Richard Saul Wurman
Information Anxiety, 1989
From the moment you know enough to talk about a product—any product, whether it’s hardware, software, a video game, a training guide, or a website—you know too much to be able to tell if the product would be usable for a person who doesn’t know what you know. As Jakob Nielsen, a strong advocate of usability in product design, puts it, “Your best guess is not good enough.” That’s why usability testing is essential.
Usability Engineering, 1993
With usability testing, we get to see what people actually do—what works for them, and what doesn’t—not what we think they would do or even what they think they would do if they were using your product. When usability testing is a part of design and development, the knowledge we get about our users’ experience supports all aspects of design and development.
This chapter presents the essentials of usability testing, which include the need to
• focus on the user, not the product
•
start with some essential definitions:
defining usability testing and differentiating the two main types of testing:
– formative testing
– summative testing
• know when to conduct small studies
•
know how to conduct small studies, which include:
defining the user profile
creating task-based scenarios
using a think-aloud process
making changes and testing again
• know when to conduct large studies
• think of usability testing as hill climbing
Focus on the user, not the product
When you focus on the user and not the product, you learn what works for your users, as well as what doesn’t work, what pleases, what puzzles, and what frustrates them. You understand your users’ experience with the product to determine whether the design matches their expectations and supports their goals.
Usability testing gives you this access to your users using your product to perform tasks that they would want to do, which are matched to goals that are realistic for them. In the testing situation, you have the chance to elicit their comments, to observe their body language (in many cases), to discover their wishes and hopes for the product, and to learn how well the product supports them in their goals. The mantra of usability testing is, “We are testing the product, not you.” Many people begin a testing session with this statement. Even if you don’t make this statement to the participant, it’s important to remember that this is the focus of testing.
Start with some essential definitions
To have a common vocabulary to talk about user experience, we need a common set of definitions for the essential words we use. These include:
• usability
• usability testing
Defining usability
The best-known definition of usability is the one from ISO, the International Organization for Standardization (9241-11): “The extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use.”
Although this definition is rather formal, as you might expect for one that has become a standard, I like it because it encompasses the three critical elements of
• Specific users—not just any user, but the specific ones for whom the product is designed.
• Specified goals—these specific users have to share the goals for the product, meaning that the product’s goals represent their goals.
• A specific context of use—the product has to be designed to work in the environment in which these users will use it.
I also like this definition because it focuses on the critical measures of usability:
• effectiveness
• efficiency
• satisfaction
Effectiveness and efficiency support the user’s need to achieve a goal for using the product with accuracy and speed. Frequently, this also means that the product supports the user in a way that is better than the current way in which the user works. This is the value-added part of usability. If the product doesn’t add value to the way in which the user currently performs tasks or needs to learn to perform tasks, then the user will have no use for the product. For instance, if the user perceives that the online bill-paying feature offered by her bank is not worth the effort to set up and use, then she will continue to write checks, put stamps on envelopes, and mail in her payments. Her rejection of the new product may be because it does not appear to be efficient, even if it proves to be effective.
Beyond effectiveness and efficiency, however, is the critical criterion of satisfaction. Although measures of effectiveness and efficiency are, to some extent, determined by the user’s perceptions of these qualities, there is no denying that the measure of satisfaction is derived wholly from the user’s perception of satisfaction. Is the user satisfied with the display of the information on...