The NDAD Thesaurus is a subject index of the catalogues and administrative histories on NDAD's website. A thesaurus is a controlled
vocabulary which relates indexing terms to each other in a hierarchy, and allows indexing to be done in a consistent way.
It is important to remember that the Thesaurus is an index of NDAD's catalogues and administrative histories. We have not directly
indexed the datasets or documents which we hold. The fact that a subject appears in a dataset or a document does not necessarily mean
that it will appear in the Thesaurus.
In most cases, this should not be a problem. Our catalogues and administrative histories are designed to describe the subject matter of
datasets and documents in our archive. Consequently, any significant subjects should be mentioned in the finding aids, and should be
indexed in the Thesaurus. Searching the Thesaurus is a way of identifying, via the catalogues and administrative histories, datasets
and documents relating to subjects in which you are interested.
The finding aids which the Thesaurus covers are:
Administrative histories
Series catalogues
Dataset catalogues
Dataset documentation catalogues.
Table catalogues (which describe the individual tables within a dataset) have not been indexed.
Relationship with the UNESCO Thesaurus
The NDAD Thesaurus is based on the UNESCO Thesaurus .
While most of the terms and relationships are derived from the UNESCO Thesaurus, some terms have been added by NDAD. The NDAD
Thesaurus distinguishes between UNESCO terms and NDAD additions. UNESCO terms are indicated by the suffix [U], while NDAD terms have
the suffix [N]. The suffix [P] is used to indicate terms which we've used which were originally added to the UNESCO Thesaurus by the
National Archives.
Not all of the UNESCO terms in the NDAD Thesaurus are terms which we've used to index our finding aids. If an indexing term has a
broader term in the UNESCO Thesaurus, we've included the broader term and any terms above it (e.g. BT1, BT2, BT3), even if we haven't
used these terms for indexing. This has been done to ensure that users searching on very general subjects will be directed downwards
to the more specific terms which we've used to index our catalogues. Check boxes (allowing you to search for catalogues) only appear
next to indexing terms. If an indexing term is an NDAD addition, we may have linked it to a UNESCO broader term which we haven't used
for indexing.
The names of corporate bodies (e.g. government departments), the names of persons, families and place names do not appear in the NDAD
Thesaurus. These terms have been indexed separately: see the Names Index.
If you want to search for a specific term in our catalogues, we recommend that you also try a free-text Search.
How to use the Thesaurus
You can search for terms in the Thesaurus in two ways:
By browsing lists of terms arranged in alphabetical order.
By browsing lists of terms arranged hierarchically by field of knowledge and microthesaurus heading.
Alphabetical searching
The Thesaurus consists of two types of terms:
Preferred terms: terms which have been used by NDAD to index our catalogues, plus any broader terms (not used by NDAD for
indexing) which have been derived from the UNESCO Thesaurus.
Non-preferred terms: the synonyms or quasi-synonyms of preferred terms, which direct you to use the preferred term. Non-preferred
terms indicate that you should search for the concept using the preferred term. E.g. "Congresses USE Conferences": "Congresses" is
the non-preferred term directing you to use the preferred term, "Conferences".
The alphabetical searching facility allows you to browse lists of the preferred terms and non-preferred terms in the Thesaurus,
arranged in alphabetical order.
In order to make the listing of terms more manageable, the terms have been divided into alphabetical groups of 40 terms each (e.g.
"Automobiles - Canals"). An initial list of term groups provides links to each individual group. Your first step in searching the
alphabetical lists is to choose the group which contains the term(s) in which you are interested. You will need to return to the list
of alphabetical groups each time you want to search on terms in another group.
Within each group, preferred terms are displayed with any or all of the following relationships. In most cases, relationships are
derived from the UNESCO Thesaurus:
Microthesaurus (MT): microthesauri are broad, top-level divisions within the Thesaurus which group related terms together. At a
minimum, every preferred term should be assigned to a microthesaurus. You can search the Thesaurus hierarchically by
microthesauri: see 'Hierarchical searching', below.
Scope notes (SN): explanatory notes about how a term should be interpreted.
Broader terms (BT): terms which sit above a term in the Thesaurus' hierarchy. These terms express more general concepts. BT1
indicates a broader term that is one level above, BT2 a broader term which is two levels above, etc.
Narrower terms (NT): terms which sit below a term in the Thesaurus' hierarchy. These terms express more specific concepts. NT1
indicates a narrower term that is one level below, NT2 a narrower term that is two levels below, etc. Although a term can have
only one broader term at BT1 level, one broader term at BT2 level, etc, it can have many narrower terms at the same level (e.g.
NT1).
Related terms (RT): terms which express a similar concept to the term in question, but which are not related hierarchically as
broader or narrower terms.
Non-preferred terms (UF): synonyms or quasi-synonyms of preferred terms
Broader terms, narrower terms and related terms have links which lead you to the full display of each term. Non-preferred terms, where
they appear individually in the alphabetical lists, link to their preferred terms.
Check boxes next to terms allow you to select terms for searching. See 'Executing searches', below for further details.
Hierarchical searching
As we have seen, terms in the Thesaurus are arranged into a hierarchy of broader and narrower terms (see 'Alphabetical searching',
above). Sitting above the terms themselves are microthesauri, which represent top-level divisions within the Thesaurus. Microthesauri
group terms together into general subject classifications: e.g. "1.10 Educational policy", "4.10 Psychology". Each microthesaurus is
numbered. The microthesauri are organised, into turn, into six broad fields of knowledge: "Education", "Science", "Culture", "Social
and human sciences", "Information and communication", and "Politics, law and economics". Every preferred term in the Thesaurus is
linked to a microthesaurus and, via the microthesaurus, to a field of knowledge.
You can search the Thesaurus hierarchically, by field of knowledge and by microthesaurus. A initial list of the six fields of knowledge
provides links to lists of the microthesauri within each field.
Your first step, in conducting a hierarchical search, is to select the field of knowledge in which you are interested. You will then
need to select a microthesaurus from the list of microthesauri in that field. This will lead, in turn, to a display of the terms in
the microthesaurus. The terms are displayed in hierarchical order: i.e. narrower terms (NT) are displayed under their broader terms.
Non-preferred terms (UF) are listed under their preferred terms. (For an explanation of broader/narrower terms and
preferred/non-preferred terms, see 'Alphabetical searching', above). As in the alphabetical lists, the hierarchical lists include not
only indexing terms, but also broader terms of indexing terms (not themselves used for indexing) which have been derived from the
UNESCO Thesaurus.
Check boxes next to terms allow you to select terms for searching. See 'Executing searches', below for further details.
Executing searches
In both the alphabetical and hierarchical lists of terms, check boxes allow you to select terms for searching. Check boxes only appear
next to those terms which we have used to index our catalogues and administrative histories (see 'What is the Thesaurus?', above).
Click on the box next to each of the terms in which you are interested, so that there is a tick next to all your chosen terms. As
appropriate, change the box (nearer the top of the screen) which allows you to specify whether the search should find finding aids
which have been indexed using ALL or ANY of the selected terms. (ALL is equivalent to a Boolean AND search, ANY to a Boolean OR
search). Click the Search button to launch the query.
Search results
The results of your search are shown as a list of links to the catalogues and administrative histories which match the search criteria.
Your query, consisting of the terms selected and whether the search was ANY or OR, is displayed at the top of the page. Each item in
the list shows the title of the finding aid which matched your search, and its size in bytes and the date of its last modification.
Each link will lead you to the catalogue or administrative history.
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