Taxonomy

Taxonomy involves using controlled vocabularies to organize and classify content. Controlled vocabularies are pre-selected sets of terms that help describe and tag content. This tagging creates descriptive metadata, which is essentially data about data.

Each time you add a new article or page to your website, you will need to use these pre-defined, controlled terms to label your content. This process occurs behind the scenes. While not directly visible to users, it helps the website's backend system understand and manage the content effectively. For example, on an information website about animals, terms like "Mammals," "Birds," and "Reptiles" are part of the controlled vocabulary. Each article is tagged with these terms to create metadata. This metadata makes it easier for the backend to sort and direct users to the right content, ensuring a smooth and organized user experience.^[1]

In information architecture, the IA structure and taxonomy serve different purposes:

• The IA structure is a map of how content is organized on a site. It shows all the pages or screens and their relationships. It's used by the design team to decide where content should go. Users don’t see this map directly — they only interact with the navigation, which is a simplified version.
• Taxonomy, on the other hand, is a map of concepts used in the backend to describe and classify content. It connects similar content pieces and shows how these concepts relate to each other. Taxonomy is more technical and detailed than the IA structure. It is used to add precise and logical classification to individual pieces of content like an article or product.

Another related concept is content or data models. These are also part of the backstage and describe the different types of content, the information they contain, how they link to other content types, and what metadata applies to them. For example, in a product page, the data model might include information such as product name, description, price, and stock availability. It would also contain relationships with other content types like the product category or manufacturer. Metadata could include details like the date the product was added, its overall customer rating, or SEO keywords.

Taxonomies offer several key benefits including:

• Content retrieval: Taxonomies help retrieve all related content for a specific concept. For example, on a recipe website, dishes categorized under "Italian Cuisine" can be easily grouped together, making it simple for users to find all relevant recipes.
• Making connections: They allow linking related content even if it’s in different navigation categories. For instance, on an educational site, lessons about "Photosynthesis" might be found under both "Biology" and "Environmental Science," but a taxonomy ensures they are all connected.
• Faceted navigation: Taxonomies enable faceted navigation, which lets users apply multiple filters simultaneously. For example, an online clothing store might allow users to filter items by size, color, and brand, helping users quickly find what they need without sifting through irrelevant items.
• Search suggestions and refinements: When users type search queries, taxonomies help provide related terms and categories. For example, a travel site might autosuggest related destinations like "Paris Hotels" and "French Cuisine" when users type "Paris," enhancing the search experience.

Before creating a taxonomy from scratch, check if a standard taxonomy for your industry or domain already exists. Using an existing taxonomy can save a lot of work and give you a head start. For example, if you work in healthcare, you might find a standard medical taxonomy that you can adapt, saving you the effort of creating one from scratch.

Here are a few things to keep in mind:

• You might need to adjust existing taxonomies to fit your specific needs.
• Some existing taxonomies are free and open source, while others can be costly and require a license.
• A good place to start looking is the Basic Register of Thesauri, Ontologies & Classifications, which lists available taxonomies you can choose from.^[2]

The most important step in putting together a taxonomy for your website is identifying the fundamental concepts that need organizing. These items or objects are sometimes called "leaves" because they are the endpoints in a hierarchy with no further subdivisions.

You can find these concepts in:

• Content: Look directly at the information and data you have.
• Existing metadata: Keywords or topics in your content management system.
• Discussions with subject-matter experts: Gather insights from those who know the field well.
• Industry terms: Identify important internal terms used by your organization and competitors.
• User data: Use information from interviews, usability testing, and search logs to ensure the taxonomy benefits users.

By gathering information from these sources, you can build a taxonomy that is both useful and relevant, avoiding the creation of unnecessary branches.

Next, build out the relationships between concepts. For a hierarchical taxonomy, this means defining the branches of your tree and deciding the parent-child relationships between concepts.

You need to decide how detailed each level should be. For example, if you’re creating a taxonomy for a library, "Books" might be a parent category. Under "Books," you could have "Fiction" and "Non-Fiction." Under "Fiction," you might have "Mystery," "Romance," and "Science Fiction." This shows how broad or narrow each category should be.

You also need to identify related concepts that aren’t synonyms. For example, "Books" and "E-Books" are related but not the same. You connect these with related-term relationships. This is crucial because it helps users find related content easily.

Using relevant terms in your taxonomy concepts makes it easier for users to find what they're looking for. If the terms are outdated or not commonly used, users might struggle to understand the categories. For example, if you're creating a taxonomy for an online clothing store, using terms like "Doublet" instead of "Jacket" would be confusing and unhelpful. Most people today don't know what a doublet is, but everyone understands what a jacket is.

Relevant terms also help in search functionality. When users type in a search query, they expect results that match current terms. If the terms in your taxonomy aren't relevant, the search results will be less accurate. By ensuring the terms are up-to-date and commonly understood, you improve the user experience. Users find information quickly and easily, leading to better engagement and satisfaction.

When determining the hierarchy in taxonomy, consider users’ journey through your website. The goal is to make navigation as intuitive and efficient as possible, reducing the number of clicks required to reach a desired page. This often involves creating broader categories with subcategories (broad and shallow hierarchy), rather than a narrow and deep list of categories.

Remember, even if it takes multiple clicks to reach a certain item, it's not necessarily a bad thing as long as users can navigate quickly and find what they’re looking for. For instance, items like wine or books often have more attributes (facets) than other items. Consequently, these might necessitate a more thorough categorization.

Striking the right balance in your hierarchy can make a significant difference in user experience. Aim for a structure that is intuitive, efficient, and user-friendly. Also consider including facets or additional filters or subcategories that allow users to refine their search within a category, based on specific attributes. They are particularly useful for large sites where the range of products or content is extensive.

Testing, reviewing, and revising your taxonomy is essential to ensure it matches the existing mental models of your users. Here are some ways to do so:

• Card sorting: Ask users to group terms in ways that make sense to them. This helps understand how users think about categories and labels, ensuring the taxonomy aligns with their mental models.
• Tree testing: Present users with a simplified version of your site's hierarchy (the "tree") and give them tasks to find specific items. Track their success rate and the paths they take to see if the structure matches their expectations.
• Usability testing: Have users perform real tasks on your site. Observe how they navigate and identify any difficulties they encounter, ensuring the taxonomy supports intuitive navigation.

Based on the feedback and data, make adjustments. Simplify categories, add missing terms, or reorganize the hierarchy. After revisions, test with users again to ensure that the improvements work.

Applying taxonomy to your content is a crucial step that requires effort and training. It is usually done within a content management system (CMS) or digital asset management (DAM) system. Here are some tips to keep in mind:

• Train your team: Make sure the people tagging content understand the taxonomy. They need to know when to use each term correctly to ensure consistency.
• Tagging content: Go through your content and assign the appropriate taxonomy labels and facets. This might be a big task, especially if you have a lot of content.
• Use AI Tools: Consider using AI tools for automatic classification to speed up the process. However, be aware that AI can make mistakes.
• Manual refinement: After using AI tools, manually check and refine the tags. This step ensures accuracy and helps catch any errors the AI might have made.

Maintaining your taxonomy is crucial to keep it effective and relevant. Here’s how to do it:

• Regular reviews: Periodically review your taxonomy to ensure it remains up-to-date. This involves checking if the categories and terms still align with your content and user needs.^[3]
• User feedback: Collect and analyze feedback from users. Pay attention to any difficulties they face in finding information, as this might indicate a need for adjustments.
• Analyze search data: Monitor search logs to see if users’ search terms match your taxonomy. Identify common searches that yield poor results and adjust the taxonomy accordingly.
• Update content: As new content is added or old content is removed, update the taxonomy labels and metadata to reflect these changes. This ensures that all content remains accurately categorized.