A usability test is a method for finding problems with an interface. The goal of usability testing is to find as many problems as you can during the test, so that you can correct them before a product is released. Usability testing is a tool to help you fix and/or refine a product.

Usability testing means different things to different people. Before you begin a usability testing project, you should discuss the project with key stakeholders and decide upon the scope and purpose of the particular test.

You can perform a test on a completed application, a hi-fi computer prototype, or a lo-fi paper prototype. If you want to test existing software before beginning the design of a new release, your test will probably be conducted using the full version of the software, running on a computer.

If you want to test for interface design problems earlier in the cycle, however, you will need to use a prototype. A hi-fi computer prototype means that the interface is being displayed on a computer, but it has to be a working model.

The advantage of testing lo-fi paper prototypes is that you can test early and don’t have to worry about the robustness of the prototype.

Usability tests can vary on the amount of interaction that the tester has with the subject.

There are two major camps of usability testing

• Low-Interaction Techniques: allow little or no interaction between the tester and the participant during the test, it is critical that users think out loud during the test, since the tester will not be able to prompt them for information.
• High-Interaction Techniques: allow the tester to interact with the participant during the test.

Since there are two basic types of media for your interface, computer and lo-fi paper prototype, and two basic types of interaction, low and high, there are four possible ways for you to conduct your test

• Computer Media with Low Interaction
• Computer Media with High Interaction
• Lo-Fi Paper Prototype and High Interaction
• Lo-Fi Paper Prototype and Low Interaction

After you choose which type of test you are going to run, you need to make a few more decisions about the testing environment:

• Will you be testing in a lab?
• Will you be video-taping the test?

A usability specification describes a particular task that the user should be able to complete and under what conditions. It also describes the criteria the task should be performed against.

Before you decide whom to test, you should discuss and decide on the critical user groups you have and who you need to get feedback from. Most projects have heterogeneous users- you may have more than one group of users who will be using the software, and these different groups may have different demographics.