Subject Authority Files

Introduction

Wellcome’s preferred subject thesaurus is MeSH (Medical Subject Headings). MeSH specialises in medicine but also includes the wider non-medical intellectual landscape. Many of its terms are intuitive but, not always: it uses the less intuitive, more technical “Neoplasms” instead of “Cancer”.

For non-medical concepts, Wellcome uses Library of Congress Subject Headings (LCSH).

As American thesauri, MeSH and LCSH use American spellings

Both MeSH and LCSH are hierarchical thesauri, with narrow terms nested below broader ones. The thesaurus that we use in CALM is simply a flat list of terms (whilst CALM can handle subject hierarchies, for historic reasons this feature has not been used).

In CALM, LCSH terms are distinguished by a paragraph tag <p> at the front, as it is important to signal to Sierra which thesaurus a term comes from. This tag is invisible on the web front-end.

Guidelines on use

Subject indexing is not a replacement for keyword searching. It should be used to highlight key terms as access points for researchers.

Subject terms are best entered at collection level, to bring the user in at the top level where an accumulation of material is most comprehensible. However, it may be appropriate to add more specific subject terms at lower levels where a section/series/item relate to a given subject.

Try to keep subject terms fairly general, as very specific indexing reduces the number of people for whom it might be useful. If you want a more specific term to be findable, include it somewhere in the catalogue record, most commonly the Description field.

Do not add more than 10 subject terms to a record.

Fewer than 5 is preferable.

Instructions on how to add subject terms to catalogue records and to the subject database are in the local CALM User Guide.