Subject headings on Ovid databases

It is important to note that individual databases index content under different subject headings. MEDLINE uses a thesaurus known as Medical Subject Headings (MeSH), Embase uses Emtree, and PsycINFO uses the American Psychological Association index terms. The table below shows how the same term is assigned in each database:

Database	Indexing system	Term	Subject heading used
MEDLINE	Medical Subject Headings (MeSH)	Heart attack	Myocardial Infarction
Embase	Emtree	Heart attack	Heart Infarction
PsycINFO	American Psychological Association index	Heart attack	Heart Disorders

Similarly, a specific search term may not exist in a database. Selecting an appropriate database for your search is important in ensuring an efficient and effective search.

Ovid database mapping is designed to prompt you with the subject heading for your concept. When you search MEDLINE (or other Ovid databases) you can identify subject headings by ticking the ‘Map Term to Subject Heading’. In CIAP this box is ticked by default.

If you choose to search for ‘alternative medicine’ for example, MEDLINE will recognise that the subject heading is ‘Complementary Therapies’ because alternative medicine is indexed under this subject heading.

For more information about the term ‘Complementary Therapies’ you can click on the scope note icon to the far right of the term. The scope note tells you that the term ‘Complementary Therapies’ is a very general term and that other, more specific terms, are included within it.

You can check the thesaurus to find out what the other terms are. Click on the subject heading term (Complementary Therapies) highlighted in blue, and the MeSH ‘tree structure’ will appear. The tree structure appears as an indented list of specific terms (the branches) that relate to the subject heading. It is not always necessary to check the structure, but the information is there if you wish to view it and may help you to choose the best terms for your search.