The goals or mandate for usability tests vary widely and greatly influence the test design. Here are some examples of possible goals for usability tests:

• Identify usability problems with a proposed software user interface (UI), estimating the frequency and severity of each problem.
• Rank three competing home networking systems on ease of setup, and explain the rankings.
• Identify problems in the packaging and directions accompanying a disk drive intended for end-user installation. Include the scenarios of installing an additional drive and replacing a computer's primary drive.
• Obtain baseline ease-of-use measures for the current release of a product, for comparison to prototypes of a future release.
• Show which of two online help system designs is more effective, and why.
• For a product on which users receive training from independent software vendors, assess product ease-of-use upon completion of a training procedure. Also identify points that should be emphasized in the training procedure.
• For a product that provides several ways to perform common tasks (e.g., via touchscreen, keyboard-only, or keyboard plus mouse), show which techniques are fastest and least error-prone among practiced users.
• For each of three spin button control designs, estimate the probability that users will choose the appropriate spin direction, for each of several types of serial values.

Example of a spin button control

A spin button control consists of two arrow buttons, pointing up and down, or right and left. A textbox, located adjacent to the arrow buttons, displays one value of a series of values, e.g., numbers in a series, or days of the week. Clicking on an arrow button causes the text box to display the next or previous value in the series.