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Usability Testing10.0101

I am currently designing an iPhone application, we have strategically planned out the complexities of the product, the user base and we are designing and developing the application, however none of us are in the medical field, and have asked, what I think would be considered “subject matter experts” to review the designs for this application. The most critical aspect of user-centered design, usability testing breaks down the wall between the designer and user, and allows us to see how real users do real tasks in the real world. There are many benefits of usability testing, including uncovering pitfalls in a current system before a redesign and evaluating the usability of a system during and after design. Usability testing should be an iterative practice, completed several times during the design and development life-cycle. The end result is an improved product and a better understanding of the users that we’re designing for.

This process will take place numberous times along the design and development lifecycle.

Below are the first steps:
Planning a Test
The first thing to know about planning a usability test is that every test is different in scope, and results will vary a lot depending on the purpose and context of the test. Testing a single new feature will look very different from testing several key scenarios in a new site.

No matter what the scope is, there are a several points that you should consider as early as possible:

  • Test with a reasonable number of participants—at least five and no more than 20. You can recruit testers yourself or hire an agency. Either way, all of your participants will expect an incentive for showing up.
  • Know how long it will take. As a guide, the total time for planning, running and analyzing is usually at least two weeks and can be as long as six weeks. The length of individual testing sessions can vary but will typically run one to one-and-a-half hours.
  • Get a location. The location of the test can be as simple as a meeting room or as complex as a purpose-built facility.

What Are You Going to Test?

Next, you need to decide what you’re going to test. The best way to do this is to meet with the design and development team and choose features that are new, frequently used, or considered troublesome or especially important. After choosing these features, prioritize them and write task scenarios based on them. A task scenario is a story that represents typical user activities and focuses on a single feature or group of related features. Scenarios should be:

  • Short. Time is precious during usability testing, so you don’t want to spend too much time on reading or explaining scenarios.
  • Specific. The wording of the scenario should be unambiguous and have a specific end goal.
  • Realistic. The scenario should be typical of the activities that an average user will do on a site.
  • In the user’s language and related to the user’s context. The scenario should explain the task the same way that users would. This emphasizes the importance of the pre-session discussion, which gives you the opportunity to understand the participant’s relationship with the site.

I will elaborate more on this topic as there are numerous books written and I will attempt to filter the core of this information. I will leave you with this, we are all somewhat familiar with the range of methods that can be used to usability test our products or even early designs. But there may be more methods than you’ve thought about. How many of the following methods are you familiar with?

  • Interviews/Observations: One-on-one sessions with users. At the Interview end of the spectrum, ask them questions about what they do. At the Observation end of the spectrum, watch what they really do. It’s often possible to conduct both types of session in the same on-site visit.
  • Focus Groups: Often used in marketing well before there is any kind of prototype or product to test, a facilitated meeting with multiple attendees from the target user group.
  • Group Review or Walk-Through: A facilitator presents planned workflow to multiple attendees, who present comments on it.
  • Heuristic Review: Using a predefined set of standards, a professional usability expert reviews someone else’s product or product design and presents a marked checklist back to the designer.
  • Walk-Around Review: Copies of the design/prototype/wireframe are tacked to the walls, and colleagues are invited to comment. (Post-It® Notes are good for this) It also works well when users are around for some other purpose, and this is the only way you can get their attention.
  • Do-it-Yourself Walk-Through: Set up a usability test situation, but without invited users. Make mock-ups of artifacts, but make the scenarios realistic. Walk through the work yourself.
  • Paper Prototype Test: Use realistic scenarios but a fake product. If possible, have a colleague “play” the insides of the product or software.
  • Prototype Test: A step up from a paper prototype, this one uses some type of animated prototype with realistic scenarios.
  • Formal Usability Test: Using a stable product, an animated prototype, or even a paper prototype, test a reasonably large number of subjects against a controlled variety of scenarios. See How Many Subjects Do I Need for a Statistically Valid Survey by Daryle Gardner-Bonneau for pointers on how to decide when you have enough subjects.)
  • Controlled Experiment: A comparison of two products, with careful statistical balancing, etc. This may be the hardest method to do “in the real world” but it’s the one you need to publish the results.
  • Questionnaires: formal questionnaire, matching questionnaire (sometimes these are similar to a card-sorting exercise), phone questionnaire. Each of these formats has pluses and minuses, with questionnaire design being a field of its own. See www.stcsig.org/usability/topics/measurement.html for more information on questionnaires.

Any usability test method will give better results with real user participation, but sometimes that just isn’t feasible. Let’s face it, even getting colleagues to join you can sometimes be difficult. However, it’s important to remember that there are many tools in your usability toolkit, and there will usually be one that can get the job done.

Methods such as User-Centered Design, Usage-Centered Design (and other variants of meaning for UCD) often incorporate one or more of these test methods into the design process. That’s all good, as is the combination of heuristic and questionnaire approaches in the accompanying articles and links supplied above.

Stay tuned for more on this topic.


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  2. ownsahi

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