Term Refinement and Targeted Selection (Term Hierarchies) – Ovid MEDLINE

Background

The structure, system and sheer depth of database controlled vocabularies also provides searchers with various means of selecting terms, of considering their relevance and of refining them so that they better suit the search at hand. To illustrate this, let us refer again to the following research question and subsequent task.

Is acupuncture effective in the treatment of migraines? Find randomised controlled trials.

Here we need to consider how to proceed with the term ‘acupuncture’. This Focused Search looks at how the MeSH thesaurus as an highly structured and contextually deep knowledge base can help researchers refine their search terms. And that via Ovid MEDLINE, the MeSH thesaurus knowledge base provides researchers with a means of being able to (a). navigate through it, (b). select specific terms and (c). remove others.   

Exact versus Near Matches:
Entered into the Advanced Search with the mapping turned on, the entry term ‘acupuncture’ yields a list of MeSH term possibilities as shown in the screen shot below. As marked by the ticked Select box, the entry term ‘acupuncture’ is an exact match. The other possibilities are near matches.

From this initial display, or by running the MesH term search in Ovid MEDLINE (line #1), it is not possible to determine whether or not Acupuncture/ has narrower terms. Running the term again but with the Explode option activated, indicates that it does not (#2).  However, Acupuncture Therapy/ does have narrower terms (compare lines #3 and #4), terms that might be more appropriate for the research question. 

Learning with Scope Notes:
The MeSH thesaurus created and cultivated by the NLM is an exceptionally information laden example of a controlled vocabulary. In addition to a hierarchical term classification scheme, rich structure and subheadings, MeSH terms also have scope notes allocated to them. This MeSH term specific annotation gives an indication of the coverage of the term (from the indexers point of view), flags points to note, provides information on the year of entry of the MeSH term into the thesaurus, indicates any previous indexing, gives references and lists other terms the given MeSH term would additionally capture when used in a search. In this Focused Search example the scope note for Acupuncture Therapy/ helpfully draws a distinction between the term ‘acupuncture’ meaning the specialty as opposed to ‘acupuncture’, a form of therapy. See lines #6 and #7. 

Targeted Term Selection:
In contrast to the MeSH term Acupuncture/ which has no narrower terms, Acupuncture Therapy/ has several. However, not all of them might be pertinent to the research question at hand. In Ovid MEDLINE it is possible to fully display the chosen MeSH term and all its narrower terms and their narrower terms, yet only select specific narrower terms. In the screen shot example below the Acupuncture Therapy/ narrower terms Electroacupuncture and Moxibustion as highlighted in red, have been excluded.

Practice Suggestions:

1. How many narrower terms are there for the MeSH term “Drug-Related Side Effects and Adverse Reactions”/?
2. How could you verify that Explode returns narrower terms as well as the narrower term of the narrower terms?
3. Would the MeSH term Deep Learning/ usefully contribute to an investigation on surface versus deep learning in medical education? How could you find out?

 

Search Stategy

Copy Strategy Launch Search

Reviewers

Primary: Michael Fanning

Secondary: Charlotte Viken

Review Date: 2024-07-15

Expiry Date: 2025-07-15

Original search produced by:

Ovid Training Team

References:

OvidGO! / Skills Videos
What is Ovid MEDLINE
Ovid MEDLINE segments explained
How to customize Ovid MEDLINE segments
How is indexing done in MEDLINE
Subject heading searching

Citation:

Ovid Customer Support, Term Refinement and Targeted Selection (Term Hierarchies) – Ovid MEDLINE, OvidGO! / Focused Searches, Version: 8th May 2024. Visited: < Insert Date >.