The UK Data Service maintains and promotes two thesauri: the Humanities And Social Science Thesaurus (HASSET) and the European Language Social Science Thesaurus (ELSST). These tools are linked to each other, with their concepts mapped for equivalency. They are accessible separately via SOLR applications.
HASSET is the subject thesaurus that the UK Data Service uses to index and search its data collection. Originally based on the UNESCO Thesaurus (ISBN: 92-3-101469-2), it has been developed by the UK Data Archive over more than 20 years.
ELSST is a broad-based, multilingual thesaurus for the social sciences. Originally based on the monolingual HASSET, ELSST has been developed over the years for use in an international setting. Its main aim is to facilitate access to data resources across Europe, independent of domain, resource, language and vocabulary.