Testing Usability for Mobile Apps: Best Practices

Usability testing reveals the places and ways your app fails.

Having a great app idea isn't enough: The app has to work! Usability testing can ensure that users of your mobile app will get the experience you intend. What should you test, though, and how should you test it? Here are the best practices for nursing your app through usability testing.

After the development of a new mobile app or website, usability testing is too often seen as a luxury, or a nice-to-have option. Unfortunately, this is a naïve perspective. User-testing can reveal whether you are providing requisite features in a way that is effective, easy, and pleasant for people to use.

What usability testing looks for can be broken down into five main components:

1. Learnability: Can your users accomplish simple tasks the first time they use your app?

2. Efficiency: Can required tasks be accomplished within a reasonable period of time?

3. Memorability: When users move through your app, are they able to return to previous tasks? After an absence for a period of time, can a user quickly replicate tasks upon returning to the app?

4. Errors: While using your app, do users make errors? Are they encountering errors within the app?

5. Satisfaction: Were users pleased with the app? What was their overall satisfaction with the experience?

Each of these items may seem straightforward or easy to accomplish when designing and building your app. However, you may be surprised at how usability testing reveals the places and ways your app fails.

How Apps Are Tested

According to the Nielsen Norman Group, usability testing your mobile app should include the following steps and considerations:

• Hardware: User testing on mobile devices presents certain challenges, not the least of which is recording the screen during the test. There are several software options for desktop computers, but this isn't the case for mobile devices (particularly considering the complexity added by touchscreens). To get around these issues, an external camera is the best solution -- although care has to be taken to make sure the screen of the device used for testing is visible at all times (which can limit mobility).
• Software: It's ideal if your camera can project what you're recording onto a secondary screen. This allows the facilitator to view the behavior of users without getting in their way. Many cameras come with software for this, but there also is a strong case for using a simple webcam to achieve these goals.
• Environment: While user testing has traditionally been conducted in an area with minimal interruption, mobile testing may be best done with some distraction since smartphone and tablet apps often are accessed in busy locations. But, be sure to choose a place where the participants can be comfortable, the cameras can be set up as required, and the facilitator can be heard.
• Participants: Choose users who have at least three months of experience with mobile devices. You want to be able to distinguish between difficulty using your app and discomfort with a mobile interface itself. It is recommended that you perform testing with a minimum of five users, preferably from outside your organization, and ideally from different demographics (while giving consideration to your target audience).
• Planning: When designing the test, be sure to include tasks that access the core functionality of your app. For example, if the app can make purchases, have testers complete sales from beginning to end. Don't forget to choose simple tasks as well, such as "Make an inquiry about shipping rates."
• Facilitation: When choosing a facilitator to execute your usability test, find one who is familiar with your objectives and the app, and who understands that the job is to communicate tasks and observe, not to help or answer questions. If the user requires clarification, this will be recorded and should tell you something important.

Evaluating Mobile App Usability Tests

After your usability study is complete, what happens next? Review the results of each user test and ask the following questions:

• Are there common failures?
• Did users get hung up on the same tasks?
• Are the failures critical?

Once you have evaluated all of the tests, the next step is to decide what changes might make a difference, and turn testing failures into successes. Sometimes all it takes to make something more intuitive is a label change for a menu item.