Tips for developing and refining a literature search strategy

• Developing a Search Strategy
• Combining terms using AND vs. OR
• Refining/Revising a Search Strategy -- Tips on how to narrow or broaden your search.
• Common Online Literature Searching Mistakes

Developing a Search Strategy

Formulate your question.

• list the major concepts that must appear in the articles
  • brainstorm synonyms for these concepts
• decide if you want a comprehensive search or just a few relevant articles
• do you want only recent articles or in any relevant material?
• are you looking for human research only?
• are you focusing on a particular population (e.g., gender, age group)?
• will you accept articles in languages other than English? (all titles and abstracts in MEDLINE and IPA are translated into English)
• are you looking for a particular type of publication (e.g., review articles, meta-analyses, clinical trials)?

Break the question down into various concepts.

• Search for one concept at a time.
• combine the concepts using "AND" or "OR" appropriately.

Use special database features.

• Medical Subject Headings (MeSH) in Medline
• Thesaurus terms in other databases
• indexing, such as dates, ages, subheadings
• IPA's Subject Categories and Pharmacologic/Therapeutic Classification codes.
• Use the Thesaurus to identify official Subject Headings for searches in MEDLINE and CINAHL.

Identify synonyms.

For each concept, list various synonyms.

• generic and trade names for drugs
• variant spellings (i.e., "estrogen" OR "oestrogen")
• abbreviations ("ALS" OR "amyotrophic lateral sclerosis")

Use truncation.

Truncation allows you to search for the root of a word and all its variant endings.

• The asterisk -- * -- is the most common truncation symbol
• for example, "diabet*" retrieves "diabetes", "diabetic", "diabetics", and so on
• truncating too soon will give you inaccurate results.
• for example, "diab*" can retrieve words like "diabolical"

Combine search concepts

Searching for one concept at a time and only then combining the sets will allow you the greatest flexibility in searching.

Using "AND"

• requires that ALL terms are present in the article.
• narrows your search (you get fewer articles than are in each set)
• example: a search for "diabetes AND insulin therapy" will retrieve articles containing both terms

Using "or"

• allows EITHER term to be present in each article
• broadens your search
• example: a search for "anorexia OR bulimia" retrieves articles that mention either condition

Refining/revising your search strategy

Narrow your search if you retrieve too many citations

• Add additional concepts to your search by adding search terms using "AND".
• Limit your search (e.g., by publication date, publication type, language, etc.).

In MEDLINE and CINAHL:

• Add subheadings to subject headings. For example, instead of searching for all articles on fluoxetine, add the subheadings "adverse effects," & "contraindications," & "poisoning," & "toxicity".

Broadening your search if you retrieve too few citations

• Eliminate peripheral concepts; use only the most important concepts in your search.
• Do not search on common words such as "therapy", "medicine", or "management".
• Identify additional search terms.
  • If you can identify one good article on your topic, examine the subject headings assigned.
  • Revise your search using those subject headings to find additional relevant articles.
  • Examine titles and abstracts of relevant articles for additional textword terms.
• Add synonyms or related terms to your search using "OR".
• Use truncation(*) on textwords to retrieve root word variations. CAUTION: Do NOT truncate Thesaurus terms (subject headings).
• Search more years worth of records, if you are not already searching the entire database.
• Apply fewer limits or no limits to your search.

In MEDLINE and CINAHL:

• Use the "EXPLODE" command to retrieve general as well as specific subject headings.
• Choose "all subheadings".
• Review the "Term Information" in the Thesaurus for related subject heading terms to include in your search.
• Include keywords as well as Thesaurus terms in your search strategy. You may need to use keywords for new therapies for which there is no good subject heading.

Common Online Literature Searching Mistakes

For additional help with your searches contact the Reference Department at 559-6221. Or contact the Education Department at 559-7075 to schedule a class or consultation.