Card sorting

Card sorting is a simple technique in usability design where a group of subject experts or "users", however inexperienced with design, are guided to generate a category tree or folksonomy. It is a useful approach for designing workflows, menu structure, or web site navigation paths.

Card sorting has a characteristically low-tech approach. The concepts are first identified and written onto simple index cards or Post-it notes. The user group then arranges these to represent the groups or structures they are familiar with.

Groups may either be organised as collaborative groups ("focus groups") or as repeated individual sorts. The literature discusses appropriate numbers of users needed to produce trustworthy results.

A card sort treats the names of the items as given. In an open card sort, the participants who do the sorting are expected to provide their own names for the categories. In a closed card sort, the participants are provided with a predetermined set of category names.

A card sort is commonly undertaken when designing a navigation structure for an environment that offers an interesting variety of content and functionality, such as a web site. In that context, the items to be organized are those that are significant in the environment. The way that the items are organized should make sense to the target audience and cannot be determined from first principles.

The field of information architecture is founded upon the study of the structure of information. If an accepted and standardized taxonomy exists for a subject, it would be natural to simply apply that taxonomy as a means of organizing both the information in the environment and any navigation to particular subjects or functions. Card sorting is applied when:

• The variety in the items to be organized is so great that no existing taxonomy is accepted as organizing the items.
• The similarities among the items make them difficult to divide clearly into categories.
• Members of the audience that uses the environment may differ significantly in how they view the similarities among items and the appropriate groupings of items.

To perform a card sort, a person representative of the audience is given a set of index cards with terms already written on them. This person puts the terms into logical groupings, and finds a category name for each grouping. This process is repeated across a population of test subjects.

Various methods can be used to analyze the data. The purpose of the analysis is to extract patterns from the population of test subjects, so that a common set of categories and relationships emerges. This common set is then incorporated into the design of the environment, either for navigation or for other purposes.

Card sorting is an established technique with an emerging literature.

See also

Short video explanation of card sorting