Usability testing is the best way to understand how real users experience your website or application.
Unlike interviews or focus groups that attempt to get users to accurately self-report their own behavior or preferences, a well-designed user test measures actual performance on mission-critical tasks. If the user cannot figure out how to complete a purchase, no amount of “but I really like the website!” comments are going to make up for it.
To conduct a usability test, begin by identifying the target audience. The target audience will consist of one or more user groups. For example, a single website may have content for consumers and a separate login area for site administrators. It is likely that these two user groups perform different tasks as part of their normal website usage. Each user group should be given tasks to perform during testing that reflect their different usage patterns.
Creating Usability Test Tasks
Typically, participants will perform a set of 5 to 10 tasks within a 90-minute session. Tasks should represent the most common user goals (e.g. recovering a lost password) and/or the most important conversion goals from the website or application owner’s perspective (e.g. making a purchase).
It is also crucial to establish very clear success criteria for each task and get stakeholder buy-in on those success criteria. An example of clear success criteria might be: “Participant must load the URL www.examplewebsite.com/purchase-success/ in their browser, and report that they believe they have successfully completed a purchase.”
It is also important to clarify where the participant should begin the task (e.g. at the home page of the website), and how task completion and starting points may affect the researcher’s ability to counterbalance task order.
Conducting a Usability Test
When conducting user testing, the researcher reads a participant one task at a time, such as “Find out how to contact technical support,” and allows the participant to complete the task without any guidance. To prevent bias, the researcher follows the same “script” when explaining the task to each participant.
The researcher may also ask the participant to talk aloud as he works on a task to better understand the participant’s mental model for the task and his decision-making in real time. When the participant has completed a task, the researcher sets up the starting point for the next task and continues the test. Ideally, task order is counterbalanced from participant to participant.
Usability Test Analysis
Usability testing recording software such as TechSmith’s Morae (PC only) or Silverback (Mac only) may be used to record the computer screen and the participant’s voice and facial expressions during testing. This software can also facilitate tracking of user behaviors, including mouse clicks, keystrokes, and active or open windows.
When all participants have completed the study, the researcher will compile the data to determine the severity of each usability issue that was encountered and provide prioritized recommendations for the development team to meet usability requirements. For example, by analyzing participants’ facial expressions, the number of mouse clicks made, and the navigation path used to complete a task, a user experience engineer can identify the most frustrating parts of a task and suggest ways to improve the interface to better support the user.
Usability testing should be conducted at various times throughout the iterative design process to ensure that all usability requirements have been met in the final product.