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The Higher Education Classification of Subjects (HECoS)

Subjects are persistent areas or branches of knowledge or learning that are studied in higher education. A new subject coding system - the Higher Education Classification of Subjects (HECoS) - has been implemented from 2019/20.  

HECoS replaces the Joint Academic Coding System (JACS), documentation and transitional mappings relating to the move from JACS to HECoS can be found in the HECoS archive.

Further information about the management of HECoS and the Common Aggregation Hierarchy (CAH) can be found in HECoS and CAH Management Guide (that can be found on the HECoS archive webpage).

HECoS Contents


The HECoS vocabulary (the current version of which is 9.0) is a single flat (non-hierarchical) list of 1,092 subject terms that ensures the categorisation of courses and modules is always performed at a consistent level. 

HECoS subject code identifiers are randomly generated and have no inherent meaning in themselves.  

Every HECoS code is associated with a subject term, a definition of that term, and where relevant, a scope note explaining the applicability of the code. This information is presented as a simple list of codes in a downloadable .csv file. 


Although the HECoS framework is a flat (non-hierarchical) structure, related codes and their corresponding term can be grouped together. 

For example, the codes 100036 (optometry), 100037 (orthoptics),100261 (ophthalmology) and 101511 (ophthalmic dispensing) are all related. 

These relationships are equable and the order in which codes are listed in the relationship documentation does not imply any hierarchy, for example, subject code 100036 is related to subject code 100037 is equal in meaning to subject code 100037 is related to subject code 100036.  For this reason, and for easy of reference, both ‘a’ is related to ‘b’ and ‘b’ is related to ‘a’ are listed in the downloadable .csv detailing HECoS relationships. 


The ‘preferred term’ used to define a HECoS code is specified in the HECoS vocabulary and can be used for classification, however, there are non-preferred synonyms, which can't be used for classification, but which may aid correct categorisation of areas of study and learning.  The preferred and corresponding non-preferred terms are published in a downloadable .csv file. 

The Common Aggregation Hierarchy (CAH) provides a standardised hierarchical aggregation (grouping) of subject codes and terms (developed based upon the HECoS codes and terms) suitable for the majority of uses.  

The CAH provides standard groupings that can be applied to both HECoS and JACS subjects allowing for consistent analysis across both coding frames. 

Commonly used and current mapping documents are available below.  

Details about these and other previously published mapping materials are available in the HECoS archive.

Main CAH webpage

In May 2021 the Foreign, Commonwealth and Development Office (FCDO) supplied HESA with a code mapping document, which came into effect on 14 May 2021, and which HESA has agreed to make available on their behalf in response to demand from our users. Whilst HESA works closely with the FCDO, it claims no responsibility for or ownership over the mapping available for download as a .csv file below. Any questions or queries regarding this information should be directed to the FCDO. 

Further information about ATAS can be found on the website or by contacting [email protected] 

The Office for Students (OfS) has produced mappings of HECoS and the Learn Direct Classification System (LDCS) to Price Groups to inform funding allocations. 

Mappings of HECoS and LDCS to Price Groups (OfS)

Mapping documentation produced and published by the Higher Education Funding Council for Wales.

Mappings of ASCS to HECoS (HEFCW)

The HECoS Archive contains information pertaining to the development of the HECoS framework and historic mapping documentation.

Link to the HECoS Archive webpage

HECoS Subject Code Search

Use this search to display the HECoS Vocabulary, preferred terms, related HECoS subject codes and associated CAH codes for an entered HECoS subject code.