Tips for Taxonomy Creation

Heather Hedden, a highly experienced taxonomist, shares her top four tips for creating a taxonomy.

A taxonomy is an increasingly common type of knowledge organisation system that arranges terms (also called concepts) into one or more hierarchies to express broader and narrower relationships. Taxonomies are developed to aid content retrieval for unique collections of content or for organization-wide information, such as on an intranet. Taxonomies are similar to classification systems, subject heading systems, and thesauri, but tend to be less formal and less complex. On the one hand, that can make taxonomies easier to create, but on the other hand, taxonomy creation needs to consider other factors and involves more decision-making. Here are my top four tips.

  • Create a taxonomy customized to the content

A taxonomy should be designed the reflect the scope and detail of a certain collection or set of content. Thus, it need not be fully comprehensive nor balanced, as a classification system is. It may be more detailed in some areas and less so in others. The names of the terms should also reflect the terminology of the content, to the extent possible. Should you use movies or films? Agreements or contracts?

  • Create a taxonomy suitable for the intended users

Who will use the taxonomy you create? Are they experts, scholars, researchers, professionals, students, or the general public? The types of users will influence your choice of taxonomy terms and the level of detail. If your users are internal, as employees or members, then you can involve them in the taxonomy-creation process through interviews of representative users and questionnaires or surveys. Interviews can reveal goals and challenges of searching for information. People who tag, classify, or index with the taxonomy are another set of users who need to be consulted in the process. User input can inform the design of the taxonomy, such as how many hierarchies or facets it should have, how many levels deep it should be, and what some of the most important terms are to include.

  • Create a taxonomy that works with the user interface

Users access may the taxonomy through a search-based application, website, content management system, intranet, etc. User interfaces vary in their ability to support taxonomy features such as multiple, dynamic filtering facets, multi-level displayed hierarchies, polyhierarchy, redirects of synonyms/variants, type-ahead display of terms, etc. Make sure your taxonomy takes full advantage of available features. Try to design workarounds where taxonomy features are lacking. Finally, push for the added programming of desired customized features, if you can.

  • Follow best practices for creating concepts and relationships

You cannot just create good taxonomy terms and relationships without some references or prior taxonomy training. Although no formal standards for taxonomies exist, there are standards for thesauri: These are also relevant for taxonomy design. ISO 25964-1:2011 Thesauri and interoperability with other vocabularies — Part 1: Thesauri for information retrieval is the current international standard, and there is an equivalent British Standard of the same name and number. A free alternative is the American standard, ANSI/NISO Z.39.19 Guidelines for the Construction, Format, and Management of Monolingual Controlled Vocabularies.

Taxonomy training through conference workshops or online training, such as the online course I offer, is a good way to learn the basics with interactive exercises. It’s important to go beyond the traditional MLIS courses on cataloguing, which focus on existing classification schemes. Taxonomies are flexible and adaptable. A good taxonomist knows when to follow the standards and when to adjust to user and business needs.