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Animals in Research: Searching Alternatives : Search Strategy


Before conducting your search it is useful to focus your research question by thinking about the following aspects of your proposed protocol:

  • The intervention or exposure
  • The disease or health problem
  • The animal species
  • Any outcome measures

In addition it would be good to think about or gether the following information:

  • General area of study
  • Species and organ system being studied
  • Synonyms, acronyms, and international spellings
  • Names of hormones, enzymes, drugs, CAS#, trade names, etc.
  • Prominent authors in the field
  • Prior knowledge of possible alternatives to use of animals or intended procedures
  • Strategies and results from previous searches

    Search by the 3 Rs

    For each of the 3 R's, you should develop one or more strategies for searching for alternatives.



    • Include research studies that use the intended topic, objective, and methodology


    • Exclude research studies that use the intended procedure (to substitute the procedure).
    • Include research studies that use the intended procedure and animal used (to improve on the procedure).

    Note:  Searches for articles illustrating Reduction and Refinement should be similar to a literature search you would perform to find all the research that has been done on your topic.  It should be a broad search that looks for different methods that have been used to conduct similar research. 


    • Exclude research studies that use animals and humans.
    • Include research studies that employ possible non-animal models/methods.
    • Exclude "higher" organisms.

    Search examples are from Chilov, Marina, Matsoukas, Konstantina, Ispahany, Nighat, Allen, Tracy Y. and Lustbader, Joyce W.(2007)'Using MeSH to Search for Alternatives to the Use of Animals in Research',Medical Reference Services Quarterly,26:3,55 — 74

    Boolean Operators

    Understanding how to correctly use Boolean operators to construct your search is important!

    boolean operators

    AND    Narrows search to only items containing both terms; best for combining 2 concepts heart attack AND aspirin
    OR Broadens search to items containing any terms; best for combining synonyms heart attack OR myocardial infarction
    NOT Narrows search to items containing 1 term but not another; use with caution dolphins NOT football


    Want to include all forms of a word in your search without typing them all in?  Truncation can help!  Most databases allow you to insert a symbol at the end of the root of a word to indicate that you would like it to retrieve any records with that word plus any ending it could have. 

    For example:

    disease* will retrieve: disease, diseases, diseased, etc.

    reduc* will retrieve: reduce, reduces, reduction, etc.


    • Each database uses different truncation symbols.  In PubMed and Web of Science you should use an asterisk(*), but in other databases like EMBASE you should use and exclamation point (!).  If you aren't sure check the help for that database.
    • Don't truncate a word too early as it will retrieve too many words that may not be relevant.  Imagine how many words start with cat*!

    Keyword vs. Subject Headings

    Keyword Searching

    • 'Google-like' searching
    • Searches for your search term anywhere in the record (may be the full text of the article, but usually is the title, abstract, authors, etc.)
    • Good for terms that are new to the field and are not a subject heading yet.
    • May be the only way to search some databases.

    Subject Searching

    • Some databases have a 'Thesaurus' of subject terms you can use to search.  In these databases each article record is assigned subject headings based on what subjects the article focuses on.
    • Using subject headings can improve your search by eliminating non-relevant results.
    • Looking up subject terms in the database's thesaurus often helps you find more narrow or broader terms, synonyms, and more.
    • Not all databases use subject terms.  PubMed, EMBASE, Agricola, and others do, but Web of Science does not.