Usability testing involves identifying key tasks performed on your web site and observing real users in a controlled environment as they complete them. Not everybody sees the web the way you do, so this is useful for identifying outstanding issues with an existing design or validating your decisions about a new one.
Usability testing is the core of good web usability. Even if you choose not to perform usability tests on your site, you will be benefiting from over a decade of their use to develop and refine best practices, inform understanding of user behavior, and generally validate the field of usability.
How is a typical usability test run? Before any subjects are recruited or given a chance to sit down at a computer, someone decides on the goals of the test, scope of the questions, and types of users to include. When users are brought into the testing facility, they are given a computer and a moderator asks them to perform tasks intended to reveal the way they interact with the site. While moderator administers the test, observers watch the user’s actions, and often also make a recording for later review. The principle is simple and easy to put into practice, but provides rich and valuable information.
Usability Testing in the Design Cycle
Usability testing is valuable at many points throughout your design cycle. When and how you choose to perform user tests depends on your needs, capabilities and resources.
- Before a Redesign
At the beginning of a redesign, testing the existing site will help you to identify successes to build on and failures to correct. - Throughout the Design Process
Performed throughout your design process, usability testing will help you to continually improve your understanding of your users, their interests and capabilities, and how they interact with your design. You don’t have to have a complete design or functional prototype to run a test. You can get creative by testing on wireframes or paper mockups. - Before Site Launch
Validating a design before launch is valuable for most projects. However, if this is the only test you run, you may not have the time or capability to fix all of the issues you identify.
Types of Testing
Usability testing falls into two main categories, qualitative and quantitative. There is, of course, plenty of room in between, and many variations within each category. Choosing the right balance is up to you.
- Qualitative Testing
Qualitative testing focuses on observation of a relatively small number of test subjects, and can reveal the majority of significant issues with a web site. It is the most common form of usability testing since it is relatively quick, cheap, and easy to perform. - Quantitative Testing
Quantitative testing focuses on quantifying metrics such as performance time, and uses larger numbers of test subjects, enough to get statistically significant results. It is best suited to refining and improving known processes rather than identifying unknown issues.
Qualitative testing itself comes in many flavors. The one most people think of is testing of a fully functional site or prototype. However, usability testing is valuable and useful long before you get to this stage of finalizing your design. Other forms of qualitative testing include:
- Testing Paper Mockups
This is often referred to as paper prototyping. The hardcopy used in these tests can range from hand-drawn wireframes paper to printouts of a more polished design. - Testing Interactive Wireframes
Several existing software programs will automatically generate interactive wireframes that can be used for usability tests.
Getting Started
This is the first of a series of articles that will focus on qualitative testing of existing sites or functional prototypes. However, the lessons covered will often be applicable to other forms of user testing, including paper prototyping, and quantitative testing. This series will cover the following major steps for usability testing, including:
- Developing a Testing Strategy
- Planning a Usability Test
- Setting up and Configuring Your Usability Lab
- Identifying and Recruiting the Right Users
- Writing a Test Script
- Prepping For Your Tests
- Running a Usability Test
- Collecting and Analyzing Your Results
- Applying Your Results