Thesaurus searching: is it worth the trouble?

Thesaurus Searching: is it worth the trouble?

What is thesaurus searching?

When searching for journal articles, a thesaurus search will attempt to match your search
terms (text or key words) to the corresponding thesaurus term (the list of subject headings
used to index items in the database). Using thesaurus terms means you should retrieve
articles that are on your topic, rather than articles that happen to contain the search word
in the title or abstract, thus ensuring a more effective search and list of relevant results.
What are the benefits?

Thesaurus terms will retrieve articles that describe the same concept in different ways.
You will retrieve articles on the subject regardless of:
• plurals (injury / injuries)
• variable spellings (orthopaedics / orthopedics, center / centre)
• use of synonyms (pressure sores / pressure ulcers / bed sores / bed ulcers / decubitus

• use of acronyms (AIDS / acquired immunodeficiency syndrome)
• Brand and generic names (Viagra / sildenafil)
What are the drawbacks?
• Different databases use different thesaurus terms that reflect its subject emphasis
• There are some occasions where a subject does not have a suitable thesaurus term
available (for example, a very new topic or one that specifically relates to the UK only)
• Thesaurus terms may not be applied to the latest articles in the database
How does this work in the NHS Healthcare Databases?

All the NHS Healthcare Databases such as Medline, CINAHL and EMBASE available
) allow you to use thesaurus
searching in advanced searching mode.
Adapted from a guide prepared by Siobahn Price, Francis Costello Library, RJAH. Revised April 2008

When you enter your text or key word in the search box, make sure you tick the ‘Map to
Thesaurus’ box before you click ‘Search’. This will allow you to select a suitable thesaurus
term from the list that appears. Note that each database uses a different thesaurus, so the
same term may not work in all databases.
How does this work in the Cochrane Library?

The Cochrane Library) allows you to search using
Medical Subject Headings (MeSH), the same thesaurus as used in Medline.
To begin a thesaurus search, click on MeSH Search below the search box, and then enter
your text or key words to search for and then click on Thesaurus to locate a suitable term
to use.

What else can I do to refine my search?

Explode

Most of the NHS Healthcare Databases offer the option to ‘Explode’ a thesaurus term.
Doing this will include all the more specific, narrower terms belonging to it. For example,
the thesaurus term in Medline for depressive disorders can be ‘Exploded’ to include
specific types of depressive disorder such as post-partum depression, as well as the
general term.
In the Cochrane Library, a thesaurus term is exploded automatically. Adapted from a guide prepared by Siobahn Price, Francis Costello Library, RJAH. Revised April 2008

Major Descriptors

Some of the NHS Healthcare Databases also allows you to choose ‘Major Descriptors’,
which will only select articles where the thesaurus term is a major aspect or the primary
focus of the article, thereby reducing the number of articles found.

Subheadings

Some of the NHS Healthcare Databases allow you to select from a list of subheadings that
limit a search to particular aspects of a topic. For example, if you are interested in diet
therapy for asthma, there is a subheading you can apply to do this.
Note that you can apply subheadings to one subject term only.
In the Cochrane Library, subheadings are available from a dropdown list called ‘Qualifiers’. Remember thesaurus searching is precision searching!
Adapted from a guide prepared by Siobahn Price, Francis Costello Library, RJAH. Revised April 2008

Source: http://www.sath.nhs.uk/Library/Documents/Library/Training/Thesaurus%20mapping%20-%20Apr%202008.pdf