Email updates

Keep up to date with the latest news and content from BMC Medicine and BioMed Central.

Journal App

google play app store
Open Access Open Badges Research article

Developing optimal search strategies for detecting clinically sound prognostic studies in MEDLINE: an analytic survey

Nancy L Wilczynski, R Brian Haynes* and the Hedges Team

BMC Medicine 2004, 2:23  doi:10.1186/1741-7015-2-23

PubMed Commons is an experimental system of commenting on PubMed abstracts, introduced in October 2013. Comments are displayed on the abstract page, but during the initial closed pilot, only registered users can read or post comments. Any researcher who is listed as an author of an article indexed by PubMed is entitled to participate in the pilot. If you would like to participate and need an invitation, please email, giving the PubMed ID of an article on which you are an author. For more information, see the PubMed Commons FAQ.

Comment on definition of 'Exp' in Table 1

Linda Slater   (2004-06-30 19:13)  John W. Scott Health Sciences Library, University of Alberta email

The following explanatory information was provided in Table 1 of this article:

"‡exp = explode, a search term that automatically includes closely related indexing terms."

Based on my understanding of Ovid and PubMed search mechanisms as well as the information provided in the Ovid On-Screen Help, the above definition of the Explode operation could be misleading. A better definition would be one of the following:

"Exp = explode, an operation that causes any conceptually narrower term(s) to be included automatically when a subject heading is searched."

or alternately,

"Exp = explode, an operation that causes subject headings that appear below the ‘parent’ term in the MeSH hierarchy to be included automatically when the parent term is searched."

In the MeSH vocabulary, 'related' terms differ from 'narrower' terms.

Narrower terms are specific types of whatever concept is represented by the original term. For example, the narrower terms for the MeSH term pain are: back pain (which in turn is the parent for the narrower term 'low back pain'), facial pain, headache, metatarsalgia, neck pain, neuralgia (parent for the narrower term 'sciatica') and pain, intractable. 'Exploding' the subject heading 'pain' will cause all the subject headings mentioned above to be included in the search.

Related terms are subject headings which are not hierarchically related (i.e. broader or narrower) to the original subject heading but which still have a meaningful relationship to the original term. 'Related' (See Also) terms are NOT included when the subject heading 'pain' is exploded. If a searcher wishes to include any related terms, they should be searched separately.

'Related' (See Also) terms for the MeSH term pain are: analgesia; analgesics; hyperalgesia; pain insensitivity, congenital and palliative care.

In PubMed, the MeSH database can be used to identify narrower and related (See Also) terms. In Ovid MEDLINE, the MeSH Tree can be used to identify narrower terms and the subject Scope Note can be used to identify Related terms.

Competing interests

No competing interests.


Post a comment