Module 5 SUBJECT SEARCHES (Controlled Vocabulary Searches)

Objectives - On completion of this module, students will be able to:

• define the term 'subject or controlled vocabulary' search
• distinguish between a keyword and a subject search
• name two standardized systems of subject headings
• identify two databases relevant to veterinary medicine that use a controlled vocabulary

Introduction:

In a subject search, your term is searched only in the Subject Headings field of the database records. These subject headings are selected from standardized lists such as The Library of Congress Subject Headings (LCSH ) or Medical Subject Headings (MESH ).

[Note - In the Libraries' catalog, veterinary medical subjects are described using LC Subject Headings. Human medical subjects are assigned both MESH and LCSH descriptors.]

A) Are keyword searching & subject searching the same? Let's compare the two.

1) To review Module 3, keywords are searched as free text in multiple fields in the database records, including the author, title, publisher, subject headings and notes fields, as seen below.

SEARCH OPTIONS	FIELDS IN A RECORD
Keyword	Title
	Author
Author	Publisher
	Year
Title	Notes
Subject	Subject Headings

2) Subject searches are a type of field search using'controlled vocabulary' descriptors. They differ from keyword searches in that:

• a subject search looks for the word(s) in only the Library of Congress (LC) or Medical Subject Headings (MESH) subject headings field as seen below; and

SEARCH OPTIONS	FIELDS IN A RECORD
Keyword	Title
	Author
Author	Publisher
	Year
Title	Notes
Subject	Subject Headings - like MESH or LCSH

• they produce more relevant results because subject headings are terms chosen by subject experts to describe topics in the most specific terms.

B) How can you find the specific subject headings assigned to an item in different databases?

1) In the Libraries' catalog, begin with a keyword search. Scroll through the resulting item records to find the relevant ones. Look at the Subject(s): field for the headings assigned to each book. Now click on the heading link(s) to bring up all books in the catalog having the same subject heading.

Example: Dunn's book has Pet medicine and Veterinary medicine assigned as its LC subject headings.

2) In CAB Abstracts, an important article database, first enter a keyword in the Thesaurus search box. (Review Module 2) The preferred term will be displayed. CAB Abstracts is a European product and uses the word 'descriptor' instead of 'subject' in its item records.

Example of a Thesaurus search in CAB Abstracts - the searcher is directed to the term 'cattle husbandry', when 'cattle management is entered.'

3) In the MEDLINE database, produced by the National Library of Medicine, enter a keyword in the search box ['heart attack' as seen in screen #1 below], and a listing of accepted subject headings from MESH (Medical Subject Headings) will be displayed. See screen #2 below.

Screen #1.

Screen #2 below shows that 'myocardial infarction' is a preferred term for heart attack..

NOTE: For an in-depth, online tutorial for either MEDLINE or CAB Abstracts, click on the title, CAB ABSTRACTS or MEDLINE.

Summary of Module 5 -

In a subject search, the term entered is searched only in the Subject Headings field of the database. Subject searches differ from keyword searches in which multiple fields are searched simultaneously.

Subject headings are assigned by subject experts for specific databases or catalogs from lists such as Library of Congress Subject Headings (LCSH) or Medical Subject Headings (MESH)

Subject searches are field searches using 'controlled vocabulary'. As such, they provide highly specific results.

Mini Test on Module 5

1. Two well known controlled vocabulary systems are Library of Congress Subject Headings and the Dewey call number system.
   True
   False
   
   
2. The term ‘descriptor’ may be used in place of the term ‘subject heading’.
   True
   False
   
   
3. The main reason for performing a search in the Subject field is to produce the highest number of results.
   True
   False
   
   

Need to review?

Module 1 - Where to Search

Module 2 - Search Basics

Module 3 - Keyword Searching using Boolean Operators

Module 4 - Field Searching