Browsing by hierarchy

This help page explains how you can browse the UK Archival Thesaurus by working through UKAT's hierarchy. This method of browsing is probably most useful if you want to view the Thesaurus' hierarchical structure. There are other help pages which explain how you can Browse by A-Z, and how to Search UKAT.

How UKAT's hierarchy works

UKAT has a hierarchical structure which is largely based on the structure of the UNESCO Thesaurus. This structure has the following elements:

Fields of knowledge. UKAT's fields of knowledge cover very broad subject areas, such as 'Education' and 'Culture'. They represent the uppermost level of the Thesaurus.

Microthesauri. The fields of knowledge are divided into microthesauri, each of which represents a subject category within a field of knowledge. A microthesaurus has a numeric identifier as well as a name (e.g. '1.10 Educational policy').

Individual preferred terms. UKAT's preferred terms are the essential building blocks of the Thesaurus (on the distinction between 'preferred' and 'non-preferred' terms, see Thesaurus basics). Preferred terms are related to each other hierarchically as broader terms and narrower terms. Broader terms represent more general concepts, and narrower terms more specific concepts. UKAT is polyhierarchical, which means that a term can potentially have more than one broader term, and can belong to more than one microthesaurus - although the majority of terms will have only a single broader term, and a single microthesaurus. A broader term can have as many narrower terms as are appropriate.

For further information about the principles underlying UKAT and other thesauri, see Thesaurus basics.

Browsing the hierarchy

Browsing UKAT's hierarchy involves starting at the uppermost level of the Thesaurus (the fields of knowledge); then moving down to the microthesauri within a field of knowledge; and then working through the levels of broader and narrower terms within a microthesaurus. Please note that the hierarchical display only includes preferred terms whose editing status is 'pending' or 'approved': that is, preferred terms which have been edited and have been formally incorporated into the thesaurus, or are awaiting incorporation following a period of consultation. The hierarchical display does not include non-preferred terms, and preferred terms whose editing status is candidate or rejected.

(1) To start browsing, select 'Browse by hierarchy' from the UKAT home page or the Thesaurus home page, or 'Browse hierarchy' from the UKAT main menu (the blue bar at the top of each page on UKAT's website, apart from the home page).

(2) Select a field of knowledge from the list of Fields of knowledge.

(3) The next page will list the microthesauri within the field of knowledge. Select a microthesaurus.

(4) The following page will display the 'top terms' in the microthesaurus: those terms which are at the uppermost level of the microthesaurus, and which therefore have no broader terms above them. The symbol indicates that a term has narrower terms. Clicking on will display the term's immediate narrower terms, expanding a section of the hierarchy. Click on the symbol to collapse the hierarchy again. A narrower term that has its own narrower term will also have , allowing you to move progressively down the hierarchy. To see all of the terms in a microthesaurus arranged according to their hierarchical position, select 'Display full list of Narrower Terms'. This list can be collapsed back to its original state by clicking on 'Display expandable list of Narrower Terms'.

Each page in the hierarchical browsing includes a string of links at the top (below the main menu), in which individual elements are separated by '>'. This 'breadcrumb trail' indicates the position of the current page in the hierarchy, and allows you to move back to previously visited levels. For example, 'home > thesaurus > fields of knowledge > education > technical and vocational study subjects' shows that the current page displays the microthesaurus named 'Technical and vocational study subjects'. Using the links, you can move back to the microthesaurus' field of knowledge ('Education'), the list of fields of knowledge, the Thesaurus' home page, and the UKAT home page. This method of navigation is also used in other areas of the UKAT website, but is particularly useful when browsing the Thesaurus' hierarchy.

UKAT uses indentation in the hierarchical lists to indicate broader-narrower relationships between terms. So in the following display:

Higher science education
Computer science education
Engineering education
Geology education
Hydrology education
Marine education

'Higher science education' is the immediate broader term of 'Computer science education' and 'Engineering education', while 'Engineering education' is the immediate broader term of 'Geology education', 'Hydrology education' and 'Marine education'. Conversely, 'Geology education', 'Hydrology education' and 'Marine education' are narrower terms of 'Engineering education'. Via 'Engineering education', they are also narrower terms of 'Higher science education', which also has 'Computer science education' as a narrower term.

Each term in the hierarchical lists links to its main display. This gives full details of the term, including those relationships which do not feature in the hierarchical browsing ('related term' relationships and relationships with non-preferred terms). See the Main term display help page for further details.