used. For example, instead of entering both “woman” and “women” as search
terms, use the wildcard entry “wom?n” instead.
Nesting, or grouping, is a strategy best used when a search contains two or
more Boolean operators. Parentheses, and sometimes quotation marks, are
used to indicate which search terms are grouped together. Just as in elementary
algebra problems, the information within the parentheses is processed first and
then applied to the information outside the parentheses. Another way to use
nesting is to place the parentheses around a phrase or proper noun to instruct
the database to search for the terms exactly as entered. For example, if searching
for information about the use of herbal remedies, entering “(herbal remedies)”
would generate records about this topic. Nesting is becoming a useful option
with many Internet search tools and databases.
In most databases, the first screen allows searchers to apply limits to fields
being searched within records, thereby filtering searches from the very start.
Limits can be set for fields such as search term, language, publication type, and
publication date. Limiting a set after an initial search creates a new, narrower
list of records drawn from the original set of records. In some databases, it is
possible to apply consecutive limits, which further narrows each subset.
Stopwords are words that are so commonly used in records that they are
a hindrance to accurate record retrieval. These words are usually articles of
speech, conjunctions, and pronouns. Although database searching has been
programmed to ignore stopwords, some databases still show “failed search”
when stopwords are used. Although stopwords can vary among databases, the
most common ones to avoid are a, an, and, for, in, of, the, this, and to.Advanced Searches: Controlled Vocabulary
Controlled vocabularies are standardized, hierarchical lists that have been
designated to represent major subject concepts and conditions contained within
a database. For a moment, consider the hashtags that you may be familiar with
from Twitter, Instagram, or Facebook. People posting comments and photos
use hashtags so that searches can retrieve items with matching content. This is
basically the same conceptual idea behind controlled vocabularies. Whereas
hashtags are chosen by those posting the photo or information, controlled
vocabularies are created by those who manage the intellectual content of the
index or database.
Vocabularies usually change from database to database. The hierarchical
nature of the lists benefits search strategies by allowing broad concepts to be
narrowed in a manner that stays consistent within that framework. CINAHL’s list
is called CINAHL Headings. MEDLINE and the Cochrane Library use Medical
Subject Headings (MeSH). Before items are added to a database, subject matterKEY TERMS
nesting: A strategy
best used when a
search contains two
or more Boolean
operators
stopwords: Words,
such as a, the,
and in, that are so
commonly used
that they can hinder
accurate record
retrieval
controlled
vocabularies:
Standardized
hierarchical lists
that represent
major subjects
within a database114 CHAPTER 4 Finding Sources of Evidence