In a human services context, a taxonomy is a classification of services arranged in a hierarchical structure, which allows an organization to index and access resources based on the services they provide and the target populations they serve. As a taxonomy provides a standard and clear way of classifying services, indexing provider services using taxonomy terms provides greater efficiency in accessing provider information. CPM supports the AIRS/211 LA County Taxonomy of Human Services, as it is widely acknowledged as the industry standard in North America. However, organizations including those outside of North America may also maintain their own taxonomies relevant to their area. Therefore CPM supports two ways of creating a taxonomy, which will be described in detail in this chapter: