RESEARCH METHOD
10 Card Sorting
When user comprehension and meaningful categorization is critical, card sorting can help clarify.1
Card sorting is a participatory design technique that you can use to explore how participants group items into categories and relate concepts to one another, whether for digital interface design or a table of contents. Participants are given cards with printed concepts, terms, or features on them, and are asked to sort them in various ways. One of the most common reasons to do a card sort is to identify terminology that is likely to be misunderstood, either because the terminology is vague or because multiple meanings are associated with it.
The card sorting method can also be used when you want to generate options for structuring your information, as it can identify different schemas for organizing your navigation, menus, and taxonomies. You can use this method to help develop frameworks that maximize the chances of users being able to find the information they need.
Card sorting can also be used to evaluate categories. The method can identify items that may be difficult to categorize or perhaps aren’t as important as others. The method validates that the categories in your product or service actually reflect the mental model of your audience, and helps them achieve their goals using words in a context that makes the most sense to them.
When running a card sort, these best practices will help in planning a successful activity:2
• Select a moderator who is familiar with the content and participants who are the target audience of the content, and who care about the information.
• Work iteratively with individual participants or small groups of participants (no more than three to five people).
• Limit the total number of participants. After 15 sessions, there are diminishing returns on the insight that can be garnered from card sorts.3
• Use 30 to 100 cards, and allow about 30 minutes for each multiple of 50 cards.
• Include blank cards and markers to allow participants to add their own items where needed.
• If there are no consistent patterns emerging after ten card sorts, consider renaming the cards, or reconsider the categories.
Your business goals probably require some sort of action on the part of your customers. However, it can be difficult for customers to act if they cannot find or understand the information you provide. A card sort can uncover how real-world usersmake sense of your “insider” or “expert” understanding. This is especially important if your content is organized with an internal view of your organization.
1. The Wisconsin Card Sorting Task (WCST) was introduced in 1946 as a means to assess patients with frontal lobe injuries, which can affect their ability to organize, plan, search, and shift cognitive sets based on environmental feedback. See:
Berg, Esta A. “A Simple Objective Technique for Measuring Flexibility in Thinking.” The Journal of General Psychology 39, no. 52, 1948: 15–22.
The Card Sorting technique was later adapted for the purposes of determining web content structure and documented by Jakob Nielsen and Darrel Sano in 1994. See: “Design of SunWeb: Sun Microsystems’ Intranet,” www.useit.com.
2. Spencer, Donna. Card Sorting: Designing Usable Categories. New York: Rosenfeld Media, 2009.
3. Nielsen, Jakob. “Card Sorting: How Many Users to Test?” 2004, www.useit.com.
4. See note 2 above.
Further Reading
Coxon, Anthony Peter MacMillan. Sorting Data: Collection and Analysis. Thousand Oaks, CA: Sage Publications, 1999.