User testing is the most effective and common form of usability evaluation. These tests involve conducting one-on-one interviews with users who represent the target demographic for the product or service. During these interviews, participants will be evaluated as they perform a series of tasks with a prototype of the proposed product. These prototypes can take the form of paper mockups, static non-functional HTML pages or fully functioning beta prototypes.

To get the most out of user testing, it is important that these tests be conducted throughout the design and development process. This process identifies usability issues earlier so that they can be corrected prior the release of the product. A usability evaluation does not need to be a complex or expensive procedure, as a user test involving 4-6 participants can identify most usability issues.

Another form of usability evaluation is the Expert Analysis. This analysis evaluates a product based on a series of defined heuristics. This type of analysis can be useful but it should not replace testing with actual users.

Typical user testing sessions include:

• Select the appropriate participants. As a result of previous user research and task analysis, a profile of your target audience should be available. The first key to success for any usability evaluation is recruiting participants that closely represent members of that target audience.
• Create an interview outline. This outline will guide the participant through the prototype and care is taken that this outline assumes an unbiased tone to preserve the integrity of the user feedback.
• Conduct the evaluation.
• Evaluate and document the test results and recommendations. After reviewing the notes and evaluation videotapes, the various usability issues will be documented. A report will be generated identifying in detail all usability issues and recommendations for improvement.