Reusable content guide

Subject headings are similar to tags or hashtags. They describe the topic of an item in a database.

However, unlike tags they come from an official, standardized set of terms and are assigned by experts.

The index of subject headings is usually called the Thesaurus. 

Many resources have their own list of subject headings, or thesaurus. For example, the database Medline has a thesaurus called MeSH (Medical Subject Headings).

• Subject headings describe the topics covered by that article rather than just the words that appear in the text
• They assigned to an article by a person, rather than a computer. 
• If you search for articles with a particular subject heading you will retrieve articles on that topic regardless of how the author described the concept
• For example, in Medline, the MeSH term Neoplasms would retrieve all articles that mention neoplasms, cancer, tumor(s), tumour etc.

• Authors describe things in different ways – an sometimes words or phrases you would never think to search for.
• Subject headings account for this by giving a consistent way of describing a topic, no matter what terms or spellings the original authors have used
• Subject headings are applied by indexers, staff working for the database
• Subject headings are only applied to records if the subject they describe is an important or substantial aspect of the article - so they help you to find relevant information.

• You type in the word for the subject/topic you’re looking for.
• The database consults the thesaurus to find the most relevant subject heading(s).
• This is called term mapping. If the list of subject heading suggested is not helpful, you could try searching again using different terms.