HRAF is pleased to announce the launch of our new Outline of Cultural Materials (OCM) service. You can find the full 7th edition of the Outline of Cultural Materials (2026) in PDF and additional formats at the following address: https://hraf.yale.edu/ocm

What is the Outline of Cultural Materials?

The Outline of Cultural Materials (OCM) is a standardized subject classification system designed primarily to categorize information about social and cultural life. The OCM can be used not only for organizing and indexing a wide variety of databases and collections, but also as a finding aid or searching tool.

When used for indexing and searching collections, the hierarchical thesaurus organization of the OCM allows one to either broaden (maximizing search results) or to narrow (maximizing precision) the focus. If you choose categories higher up in the hierarchy, all the descendants of the category and its subcategories will also be included, thus increasing the number of results. If you choose categories further down in the hierarchy, only those chosen narrower categories and their descendants, if any, will be included, thus increasing precision.

If you search for and click on a subject – e.g. Spirits and Gods – the subject category page will direct you to both the broader category; related subjects in the OCM that are not part of the hierarchy; a scope note; and a list of non-preferred terms.

In brief, the OCM subject category (or concept) is the fundamental building block of the OCM thesaurus. The OCM subject category has the following parts:

• A numeric identifier, also called OCM code
• a preferred term
• a Scope Note describing the scope of the material that is indexed with this category
• a broader category with corresponding Broader Term and broader term identifier
• a list of narrower categories with their corresponding Narrower Terms and narrower term identifiers
• a list of non-preferred terms, also called Use Fors (This functions much like an index in a printed text.)

Keep in mind that OCM subjects are almost always broader than any keyword. For example, imagine that an artifact or file being cataloged using the OCM represented “monotheism”. The OCM category Spirits and Gods would best fit this purpose. Spirits and Gods is part of a broader category, Religious Beliefs. This indicates that the OCM is organized as a two-level hierarchy, Religious Beliefs being the broader category and Spirits and Gods being the narrower one.

What’s New?

Previously, the OCM was a static resource. In order to find the updated scope notes or any newer codes, such as 1210 Archaeological Excavation Methods, the best way to do so was via the eHRAF Browse Subjects view. Our new OCM service functions as a direct way to have access to the full latest edition of the OCM as a standalone service separate from browsing the eHRAF databases. In addition to an up-to-date PDF format available for download, the OCM service offers three ways to explore the OCM:

Alphabetical Display: All terms, whether preferred or non-preferred, are organized as a single alphabetical sequence.

Major Subjects (Classified Display): The approach of arranging thesaurus terms by disciplines or subject fields similar to a library classification. When applied to a thesaurus, categories of concepts should be grouped initially to reflect the various fields of interest of its users.

Hierarchical Display: A hierarchical display shows an array of narrower terms under its parent broader term.

Major Subjects view is the broadest way to explore the OCM. Following the major threads of anthropological foci of research, Major Subjects suggests which OCMs to check from the most general to the most specific. Therefore, if you want to explore a concept like “social relationships”, 550 Naming, Prestige, and Status Mobility; 560 Social Stratification; 570 Interpersonal Relations; 890 Gender Roles and Issues; and 920 Diaspora Interactions and Interrelations are great places to begin. The related and narrower terms found within these OCMs can further refine your question.

The hierarchical display is the best way to understand the organization of the OCM, which can also help with exploring topics related to one another. For instance, 420 Property is found with 421 Property System, 424 Changes in Property Rights, and 428 Inheritance. This shows the nuances already categorized in terms of the general concept of Property and how closely related Inheritance is conceived to Property. Note that both the major subjects and alphabetical displays illustrate how a category can function on multiple conceptual planes. For instance, 428 is also a “Use For” for inheritance of responsibilities.

The alphabetical display is the most granular and functions as a list of specific ways to find and explore a topic. These are taken directly from analyst decisions during paragraph categorizing and function as an index would. For instance, if you are researching malaria, you might consider 750 Sickness to be an obvious place to start. However, analyst suggestions indicate that you may want to refer to 164 Morbidity for statistics around its occurrence, 744 Public Health and Sanitation for public health programs, 757 Medical Therapy for treatment of malaria and 734 Invalidism since malaria is often a chronic condition.

History

The OCM was first developed by George P. Murdock and colleagues in the 1930s at Yale’s Institute of Human Relations as part of the development of the Cross-Cultural Survey, a database of ethnographic information designed for scholarly research into cultural and social life across a worldwide sample of societies. The database continued to be developed by the Human Relations Area Files, which became a separate organization in 1949. In addition to its use in the eHRAF World Cultures and eHRAF Archaeology databases, the OCM can be used for many purposes within and beyond anthropology, such as subject-indexing field notes or museum collections. For example, the American Anthropological Association uses HRAF’s OCM taxonomy to facilitate searching across AAA publications, meetings, the Open Anthropology Research Repository and member profiles. As such, in addition to being a classifying system, it is also a terminology cross-referencing system.

Terms of Use

Human Relations Area Files, Inc. (HRAF) reserves exclusive rights to the title “Outline of Cultural Materials” and its contents. Should you wish to license the OCM for reuse or to modify its contents in any way, permission must be granted by HRAF. For the full Terms and Conditions and to submit a request, contact hraf@yale.edu.