Card sorting is an optional research activity, which works well for projects that involve presenting and navigating vast amount of structured data, such as in retail, manufacturing, construction, and other domains that involve finding items in large catalogs.

This method can help resolve very specific research questions for which the design team does not have a definitive answer due to ambiguity, conflicting approaches, or lack of sufficient knowledge. Examples for such questions are as follows:

• What should be the order of menu items of an application?
• Which terminology do users expect or prefer, especially in navigation elements and on call for action buttons--for example, Log In, Login, or Sign In?
• Of a list of features a product could support, which are the most important?