information-architecture

Information Architecture

Design and validate information structures that help users find and understand content.

When to Use This Skill

Use this skill when:

• Information Architecture tasks - Working on design information architecture - site structure, navigation, card sorting, tree testing, taxonomy, labeling systems, and findability
• Planning or design - Need guidance on Information Architecture approaches
• Best practices - Want to follow established patterns and standards

MANDATORY: Skill Loading First

Before answering ANY information architecture question:

2. Use established IA methodology (Rosenfeld & Morville, Abby Covert)
3. Base all guidance on validated IA practices

IA Foundations

The Four Systems of IA

System	Question Answered	Components
Organization	How is content grouped?	Schemes, structures, taxonomies
Labeling	What do we call things?	Labels, terminology, naming
Navigation	How do users move around?	Menus, links, breadcrumbs
Search	How do users find specific items?	Search UI, indexing, results

IA Deliverables

Deliverable	Purpose	When
Content Inventory	Audit existing content	Discovery
Site Map	Hierarchical structure	Design
Taxonomy	Classification scheme	Design
Navigation Model	Menu and wayfinding	Design
Wireframes	Page-level IA	Design
Card Sort Results	User mental models	Validation
Tree Test Results	Findability validation	Validation

Organization Systems

Organization Schemes

Scheme	Description	Example
Exact	Objectively defined	Alphabetical, chronological, geographical
Ambiguous	Subjectively defined	By topic, audience, task, metaphor
Hybrid	Combination	Primary navigation + search + filters

Organization Structures

graph TD
    subgraph Hierarchical
    A[Top] --> B[Category 1]
    A --> C[Category 2]
    B --> D[Sub 1.1]
    B --> E[Sub 1.2]
    end

    subgraph Database
    F[(Products)] --> G[Filters]
    F --> H[Sort]
    F --> I[Search]
    end

    subgraph Hypertext
    J[Page A] <--> K[Page B]
    K <--> L[Page C]
    L <--> J
    end

Hierarchy Depth Guidelines

Depth	Use Case	Considerations
Flat (2-3)	Simple sites, mobile	Easy to scan, limited content
Medium (4-5)	Most websites	Balance breadth/depth
Deep (6+)	Large catalogs, documentation	Risk of getting lost

Rule of thumb: Prefer broader over deeper. Users can scan 5-7 items quickly.

Card Sorting

Card Sort Types

Type	Description	Best For
Open	Users create their own categories	Discovery, understanding mental models
Closed	Users sort into predefined categories	Validating proposed structure
Hybrid	Predefined categories + can add new	Validating with flexibility

Running a Card Sort

Preparation

// Card sort configuration
public class CardSortStudy
{
    public Guid Id { get; init; }
    public required string Name { get; init; }
    public required CardSortType Type { get; init; }
    public required List<Card> Cards { get; init; }
    public List<Category>? PredefinedCategories { get; init; } // For closed/hybrid
    public bool AllowNewCategories { get; init; } // For hybrid
    public int TargetParticipants { get; init; } = 30;
}

public record Card(int Id, string Label, string? Description = null);
public record Category(int Id, string Name, string? Description = null);

public class CardSortResult
{
    public required Guid ParticipantId { get; init; }
    public required List<CategoryAssignment> Assignments { get; init; }
    public required List<Category> CreatedCategories { get; init; } // Open/hybrid
    public TimeSpan Duration { get; init; }
    public string? Feedback { get; init; }
}

public record CategoryAssignment(int CardId, int CategoryId, int? SortOrder = null);

Card Selection Guidelines

• 15-40 cards typical for open sort
• 30-60 cards manageable for closed sort
• Use real content labels, not placeholders
• Include mix of "easy" and "difficult" items
• Avoid duplicate concepts

Card Sort Analysis

Similarity Matrix

Shows how often cards were sorted together:

         Card A  Card B  Card C  Card D
Card A     -      85%     12%     45%
Card B    85%      -      10%     50%
Card C    12%     10%      -      90%
Card D    45%     50%     90%      -

Cards frequently sorted together should likely be grouped.

Dendrogram (Hierarchical Clustering)

              |
      ________|________
      |               |
   ___|___         ___|___
   |     |         |     |
Card A  Card B  Card C  Card D

Shows natural groupings and relationships.

Category Analysis

For open sorts, analyze:

• Category names - What labels do users create?
• Category frequency - How many users created similar categories?
• Standardized categories - Group similar labels together

public class CardSortAnalysis
{
    public required int TotalParticipants { get; init; }
    public required Dictionary<(int CardA, int CardB), decimal> SimilarityMatrix { get; init; }
    public required List<DendrogramNode> Dendrogram { get; init; }
    public required List<CategoryPattern> DiscoveredPatterns { get; init; }
    public required List<ProblematicCard> DifficultCards { get; init; }
}

public record CategoryPattern(
    string StandardizedName,
    List<string> Variations,
    List<int> CardIds,
    int Frequency
);

public record ProblematicCard(
    int CardId,
    string Label,
    decimal Disagreement, // How often it was sorted inconsistently
    string Issue // "Ambiguous label", "Fits multiple categories", etc.
);

Tree Testing

What is Tree Testing?

Users navigate a text-only version of your hierarchy to find items. No visual design, just structure.

Running a Tree Test

public class TreeTestStudy
{
    public Guid Id { get; init; }
    public required string Name { get; init; }
    public required TreeNode Root { get; init; }
    public required List<TreeTestTask> Tasks { get; init; }
    public int TargetParticipants { get; init; } = 50;
}

public class TreeNode
{
    public int Id { get; init; }
    public required string Label { get; init; }
    public List<TreeNode> Children { get; init; } = [];
    public bool IsCorrectAnswer { get; set; } // For current task
}

public class TreeTestTask
{
    public required int Order { get; init; }
    public required string TaskDescription { get; init; }
    public required List<int> CorrectAnswerPaths { get; init; } // Multiple valid paths
}

public class TreeTestResult
{
    public required Guid ParticipantId { get; init; }
    public required int TaskId { get; init; }
    public required List<int> PathTaken { get; init; }
    public required int FinalSelection { get; init; }
    public required bool IsDirectSuccess { get; init; } // Found it first try
    public required bool IsIndirectSuccess { get; init; } // Found after backtracking
    public required TimeSpan Duration { get; init; }
}

Tree Test Metrics

Metric	Definition	Target
Success Rate	Found correct answer	>80%
Directness	Found without backtracking	>60%
Time	Seconds to complete	Task-dependent
First Click	Correct first navigation	>60%

Pietree Analysis

Visualize where users went for each task:

Task: "Find return policy"

Customer Service [45%] ✓ Correct path
├── Returns [40%] ✓
├── FAQ [3%]
└── Contact [2%]

Help [30%]
├── FAQ [20%]
└── Contact [10%]

Account [15%] ✗ Wrong tree
└── Order History [15%]

About [10%] ✗ Wrong tree
└── Policies [10%]

Identifying Problems

Pattern	Indication	Solution
Low success, low directness	Wrong location in hierarchy	Restructure
Low success, high first-click	Right area, wrong label	Rename
High success, low directness	Findable but confusing path	Simplify
Split decisions	Ambiguous placement	Cross-reference or restructure

Navigation Design

Navigation Types

Type	Purpose	Example
Global	Site-wide access	Header menu
Local	Section-specific	Sidebar in current area
Contextual	Content-related	"Related items" links
Utility	Tools/account	Login, cart, help
Footer	Secondary access	Policies, contact
Breadcrumbs	Location awareness	Home > Products > Shoes

Navigation Patterns

// Navigation model
public class NavigationStructure
{
    public required List<NavItem> GlobalNav { get; init; }
    public required List<NavItem> UtilityNav { get; init; }
    public required List<NavItem> FooterNav { get; init; }
    public Dictionary<string, List<NavItem>> LocalNav { get; init; } = [];
}

public class NavItem
{
    public required string Label { get; init; }
    public required string Url { get; init; }
    public List<NavItem>? Children { get; init; }
    public bool IsCurrentSection { get; set; }
    public string? Icon { get; init; }
    public NavItemType Type { get; init; } = NavItemType.Link;
}

public enum NavItemType
{
    Link,
    Dropdown,
    Megamenu,
    Flyout,
    Button // For CTAs like "Sign Up"
}

Mega Menu Structure

For sites with many categories:

┌─────────────────────────────────────────────────────┐
│ PRODUCTS ▼                                          │
├─────────────────────────────────────────────────────┤
│ ┌──────────────┐ ┌──────────────┐ ┌──────────────┐  │
│ │ Category A   │ │ Category B   │ │ Catego

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