Dendrogram

A dendrogram is a tree-shaped diagram that shows how items cluster together based on card sorting results. It's one of the most useful visualizations for analyzing card sort data.

How to Read It

• Items at the bottom are individual cards
• Branches connect cards grouped together
• Height of branches shows agreement strength
• Cards grouped early (low) = strong agreement
• Cards grouped late (high) = weak agreement

What It Reveals

Strong clusters: Cards that belong together

• Short distance between merge points
• Most participants grouped these
• Natural categories emerging

Weak relationships: Cards with unclear homes

• Long distance before merging
• Participants disagreed on grouping
• May need reconsideration

Example Interpretation

If "Login" and "Sign Up" merge early (low on tree):
→ Most participants grouped these together
→ Strong candidate for an "Account" category

If "Help" merges late (high on tree):
→ Participants put it in different places
→ May need its own global navigation spot

Using Dendrograms

1. Identify natural groups: Look for early merges
2. Find outliers: Items merging late may not fit
3. Determine category count: Cut the tree at different heights
4. Validate category names: Use participant labels for clusters

Limitations

• Doesn't show category names participants used
• Can be hard to read with 50+ items
• Doesn't reveal why participants grouped items
• Best combined with other analyses

Free Card Sort automatically generates dendrograms for your studies - no manual analysis needed!