Open vs Closed Card Sorting: Complete Comparison

Quick Summary

Winner: Hybrid Card Sorting for most users because it combines the exploratory benefits of open sorting with the validation capabilities of closed sorting.

However, if you're in the early stages of information architecture development, Open Card Sorting might be better. If you're validating an existing structure, Closed Card Sorting is more appropriate.

Both methods serve different purposes in the UX research process, and the ideal approach often involves using them sequentially rather than choosing just one.

Comparison Table

What is Card Sorting?

Card sorting is a UX research method where participants organize content items into groups that make sense to them. It helps researchers understand users' mental models and expectations about how information should be organized.

The two primary methods—open and closed card sorting—serve different purposes and yield different insights. Understanding when and how to use each method is crucial for effective UX research.

Open Card Sorting Explained

In open card sorting, participants are given content items (cards) and asked to group them into categories that make sense to them. They also name these categories themselves.

Pros:

✅ Discovers unexpected mental models and terminology ✅ Uncovers natural grouping patterns among users ✅ Minimizes researcher bias in category creation ✅ Reveals vocabulary and terminology users naturally use ✅ Provides fresh perspectives on content organization

Cons:

❌ Results can be messy and difficult to analyze ❌ Different users may create widely varying categories ❌ Requires larger sample sizes for reliable patterns ❌ More time-consuming to conduct and analyze ❌ May not validate specific structural hypotheses effectively

Closed Card Sorting Explained

In closed card sorting, participants are given both content items (cards) and predefined categories. Their task is to sort the items into these existing categories.

Pros:

✅ Validates existing or proposed information architecture ✅ Produces more consistent, easier-to-analyze results ✅ Requires less time from participants to complete ✅ Needs smaller sample sizes for reliable insights ✅ Directly tests specific hypotheses about categorization

Cons:

❌ Doesn't discover new category structures ❌ May introduce researcher bias through predefined categories ❌ Participants might force cards into ill-fitting categories ❌ Limited insights into users' natural mental models ❌ May miss opportunities for innovative organization patterns

Hybrid Card Sorting Explained

Hybrid card sorting combines elements of both open and closed methods. Participants sort items into some predefined categories but can also create their own categories as needed.

Pros:

✅ Balances discovery with validation ✅ Provides structured data while allowing for unexpected insights ✅ Gives participants more flexibility than closed sorting ✅ Can validate some categories while exploring others ✅ Often yields more actionable results than pure open sorting

Cons:

❌ More complex to set up and explain to participants ❌ Analysis is more complicated than with closed sorting ❌ May still introduce some researcher bias ❌ Requires careful planning of predefined categories ❌ Can be confusing for participants if instructions aren't clear

When to Use Open Card Sorting

Open card sorting is most valuable when:

1. Starting from scratch: Developing information architecture for a new website or application.
2. Exploring user mental models: Understanding how users naturally conceptualize and categorize your content.
3. Naming navigation items: Discovering what terminology resonates best with your audience.
4. Major redesigns: Rethinking the entire information structure of an existing product.
5. Diverse user base: Understanding different mental models across various user segments.

When to Use Closed Card Sorting

Closed card sorting works best when:

1. Validating structure: Testing an existing or proposed information architecture.
2. Refining categories: Making improvements to established category systems.
3. A/B testing: Comparing two different organizational approaches.
4. Late-stage design: Confirming decisions before implementation.
5. Specific hypothesis testing: Checking if certain items belong in certain categories.

When to Use Hybrid Card Sorting

Hybrid card sorting is ideal when:

1. Partial structure exists: Some categories are well-established but others need exploration.
2. Complex information ecosystems: Large websites with diverse content types.
3. Mid-stage design: After initial open sorting has established some categories.
4. Balancing flexibility and structure: When you want controlled exploration.
5. Progressive disclosure: Understanding both primary and secondary navigation patterns.

Analysis Approaches

Analyzing Open Card Sort Results

Open card sorting typically requires more qualitative analysis and pattern recognition. Look for:

• Frequently co-occurring items
• Common category names
• Clusters of similar categorization behaviors
• Outliers and unusual groupings that might signal confusion

Tools like dendrograms, similarity matrices, and cluster analyses help identify patterns across participants.

Analyzing Closed Card Sort Results

Closed card sorting yields more quantitative data that's easier to analyze:

• Agreement percentages for each item's placement
• Success rates for finding specific items
• Time-to-completion for sorting tasks
• Confusion matrices showing where participants struggled

Statistical significance can often be calculated with smaller sample sizes than open sorting.

Analyzing Hybrid Card Sort Results

Hybrid analysis combines both approaches:

• Quantitative analysis for items placed in predefined categories
• Qualitative analysis for newly created categories
• Comparative analysis between predefined and created categories
• Pattern recognition across participant behaviors

Sample Size Considerations

For statistically significant results:

• Open card sorting: 15-30 participants recommended
• Closed card sorting: 10-20 participants typically sufficient
• Hybrid card sorting: 15-30 participants recommended

However, even smaller studies (5-10 participants) can reveal valuable insights, especially when combined with other research methods.

The Verdict

Rather than declaring a single "winner," the most effective approach is to understand each method's purpose and use them at the appropriate stage of your design process:

1. Start with open card sorting during early phases to discover user mental models and natural categorization patterns.

2. Follow with hybrid card sorting when you have initial category ideas but want to remain flexible to user input.

3. Finish with closed card sorting to validate and refine your final information architecture.

The "best" method depends entirely on your research goals, project phase, and specific questions you're trying to answer.

For comprehensive UX research, consider implementing all three methods sequentially throughout your design process for the most robust information architecture.

Try Free Card Sort for Your Next UX Study

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With intuitive analysis tools, shareable results, and no complicated setup, you can start gathering valuable insights about your users' mental models today.

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