Experiment & Research Method
Card Sorting
Card sorting reveals how users group and label content so you can design an information architecture that matches their mental model.
- Fidelity
- Medium
- Effort
- Low
- Time to run
- 1–2 weeks
What is a Card Sorting?
Card sorting is a research method for designing or evaluating information architecture. Participants organize labeled cards (topics, pages, features) into groups that make sense to them and, often, name those groups. The patterns across participants reveal how users naturally categorize your content — which is frequently very different from how your team does.
It comes in three flavors: open (participants create and name their own groups), closed (they sort into your predefined categories), and hybrid.
When to use it
Good fit
- You are designing or restructuring navigation and information architecture.
- You want labels and categories that match users’ mental models.
- Users struggle to find things and you suspect the structure is the cause.
Reach for something else when
- You need to test whether users can complete tasks in a live design (use tree testing or usability testing).
- The content set is tiny and the grouping is obvious.
- You need visual or interaction feedback rather than structural insight.
How to run it
Choose open, closed, or hybrid
Use open sorts to discover categories, closed sorts to validate an existing structure, and hybrid to do both.
Select representative content cards
Include a manageable, representative set of items with clear, unbiased labels — avoid leading category hints.
Recruit and run the sort
Have participants group the cards (and name groups in open sorts), moderated or unmoderated via a tool.
Analyze grouping patterns
Use similarity matrices and dendrograms to see which items consistently cluster together and where labels diverge.
Translate into an information architecture
Turn the strongest patterns into a proposed structure, then validate it with tree testing or usability tasks.
What you'll learn
How users naturally group and label your content, and where their mental model diverges from your current structure — the foundation for intuitive navigation.
Frequently asked questions
What is the difference between open and closed card sorting?
In an open card sort, participants create and name their own groups, which is ideal for discovering categories. In a closed card sort, they sort items into categories you provide, which is ideal for validating an existing structure. Hybrid sorts combine both.
How many participants do you need for card sorting?
Around 15–30 participants per user group is a common guideline for quantitative card sorts, enough for stable clustering patterns to emerge. Open sorts can surface useful themes with fewer, but larger samples make the similarity data more reliable.