Expert appraisal is the evaluation of a product or service by someone who has the professional training or experience to make an informed judgement on the design. Ideally, this person should not be biased by former involvement with the product since familiarity with any product or task makes it seem simpler and easier. Expert appraisal can be used to

• Identify possible causes of design exclusion
• Suggest improvements to reduce this exclusion
• Increase user satisfaction

Experts may include usability professionals, engineers, other designers, or experts with suitable knowledge of the product type or its particular environment. It is essential that the expert has a sound knowledge of the range of users that need to be considered and the circumstances of their interaction. Achieving reliable results through this method often requires the participation of several specialists, so that different perspectives and problems can be identified.

It is desirable to have an internal ‘user champion’ who can provide information about the user’s perspective throughout the design process. Expert appraisal is usually used to detect critical problems and to provide priorities for exploration with users. However, it can also provide valuable improvement suggestions throughout the design process.