Literature Review Toolbar
Lesson S-1

Overview of Modern Search Strategies

The research literature in the United States and abroad has been expanding exponentially.  This introductory lesson and the following nine Search lessons (S-2 to S-10) will help you find what you need efficiently. 

What is a Good Search?

The answer depends on the purpose of the search.  For a research paper in a masters degree course, it often is a search that locates several authoritative studies on the topic.  For the literature review of a dissertation, a good search locates at least most of the first-rate research literature on the topic, perhaps some additional scholarly and professional literature on the topics, and perhaps some first-rate literature on topics closely related to yours. 

It is rare that you can find a search tool and target the search so well that it finds all that you want and little else.  If you target narrowly, you are likely to miss some valuable literature.  If you do a broad search, you may find thousands of citations, most of which will not be relevant. 

Which Search Tools Are Best?

There are hundreds of tools for searching the social science literatures. Most are now available on the Web. Web search engines like AltaVista, Excite, HotBot, NorthernLight, and Yahooallow you to search for literature on the Web, but only a small portion of the research literature is currently publicly available on the Web.  Indexes to the scholarly literature in a given discipline, such as ERIC for education and PsycINFO for psychology, provide broad and deep coverage of the literature in their field, but generally provide only citations and abstracts online, rather than the full text of the reports. ABI/Inform provides similar breadth and depth in the areas of human resource development and management, and does provide the full text for many of the indexed journals.  UMI Dissertation Abstracts indexes and provides an abstract of most North American doctoral dissertations.  A variety of other search tools can also be useful, such as Associations Unlimited, GOVBOT, the Library of Congress Catalogue, and PolicyFile

The several Search lessons on this Web site offer instructions in how to use the search tools that are most useful for locating the research literature in the fields of education, human development, and human resource development.  These tools can also be useful when searching related fields in the social sciences.  Some of the described tools are publicly accessible without charge on the Web.  Others are available only through libraries or other organizations that subscribe to them.  All the tools described in the following Search lessons were available in Fall 1999 either publicly or privately to the The George Washington University community through the Gelman Library web page at www.gwu.edu/~gelman

How Can I Appropriately Target My Search?

The following is a good strategy for targeting a search, and it is usually best to undertake the steps in the order that they are listed.  Steps (1) – (5) are usually sufficient when preparing a paper for a masters degree class.  Steps (6) – (7) are generally expected for reviews of the literature that are part of dissertation research. 

  1. Define your topic(s).  State the topic(s) of interest and then find synonyms for each.

  2.  
  3. Determine which search tools are likely to best serve the purposes of your search.  Each of the subsequent Search lessons on this Web site indicate the main advantages and disadvantages of the described tools.  Generally Web search engines, such as AltaVista, NorthernLight, and Yahoo, are best for a quick take on topics of public interest. ERIC, PsycINFO, and ABI/Inform are the best ways to find most of the “heavy duty” scholarly and professional literature in education, psychology, and business, respectively.  Various other search tools allow you to search for the Web sites of professional associations, government agencies, and research centers, and those Web sites often include the full text of reports.

  4.  
  5. Keep careful notes of the exact searches that you specified with each tool.  Use the selected tools to search the terms developed in (1).  [Sometimes you can save the search statements for re-use or subsequent modification.]

  6.  
  7. Scan the abstracts of the “hits” from the searches.

  8.  
  9. If the initial results are not satisfactory, refine and re-run the searches. If you found too few appropriate documents or too many to scan, see the First Aid hints below.  If the initial searches found at least a few highly appropriate documents, re-run the search using the “identifiers," "index codes," "keywords" or other descriptors that were most commonly assigned to the appropriate hits.

  10.  
  11. Based on your experience in (1) – (5) use UMI Dissertation Abstracts to search for applicable dissertations. (This is not necessary if you previously searched with PsycINFO). Consider also using a few of the other search tools described in Lesson S-7.

  12.  
  13. “Snowball” your search.  This can be done in at least three ways. Check the found literature that is most applicable for references to other literature that might be useful.  Use the Social Science Citation Index to find literature that cites the best literature that you have already found.  Based on the found literature, identify the scholars who most actively do work related to your topic, and contact them to learn if they, or others they know, have recently completed applicable work that has not yet been published.
Complex Searches:

The simplest searches use a single word and often yield an unmanageable number of hits.  Complex searches use multiple words, but the complexity arises not from the number of words, but rather the logical relationship you intend to specify among them and by the syntax that the search tool requires for representing that relationship.  To complicate matters, the various search tools differ some in the syntax that they require. 

There are five common relationships between multiple words in a search statement.  They are described in order from those relationships that result in a broad search to those that result in a narrow search. 

“OR” relationship: This means that you want to find resources that are indexed by any of the words in the search term.  EXAMPLE: test OR books -- This will find all resources associated with the term "test" and also all associated with the term "books".  Some of the found resources will be associated with both terms, but some will have only one of them. 

“AND” relationship: This means that you want to find resources that are indexed by both the words in the search term.  EXAMPLE: test AND book--This will find only the resources that are associated with both of the terms.  Note that counter-intuitively, this is a narrower search than one with a "OR" relationship.

“NEAR” relationship: This is the same as an “AND” relationship except the different words have to be in close proximity (usually within about 5 words of each other).  EXAMPLE: test NEAR book--This will find only the resources associated with both terms found close together such as "test books," "test of books", "books having a test", etc.

“NOT” relationship: This means that you want to find resources that are indexed by the word(s) prior to the "NOT" in the search term and are not indexed by the word(s) following the "NOT".  EXAMPLE: test NOT book--This will find all resources associated with the term "test" except those also associated with the term "books".  This is also a narrower search than one with an "OR" relationship. 

Phrase relationship: This means you are only interested in resources that are indexed by a specific phrase--a string of words in the exact order specified in the search term.  EXAMPLE: test book--This finds only resources associated with those two words juxtaposed in that order.

It is possible to combine three or more words with two or more relationships.  For instance, special education AND teacher NEAR preparation. 

Important Note: Not all search systems support all the above five search relationships. Not all specify the relationships with the terms indicated above.  Finally, when two or more relationships are specified, the order in which they are executed will affect the results, and that order will depend on the search tool and perhaps how you exercise the option to specify the order.  When you need to use compound search statements, make sure to read the documentation for the search mechanism to see how to correctly specify the search. 

Domains of the Search

Searches for literature often can search different parts of the database records for the indexed resources.  These parts are described in the order from those that usually result in a narrow search to those that usually result in a broad search. 

Search specified citation fields: This scans citation fields such as those for title, author, classification codes, and descriptors.  Some search systems refer to descriptors as "index terms" or "keywords".

Search the abstract: This scans the text of the abstract of the publication, if one is available.

Search the full text: This scans all the text of the full publication, if it is available in the database.

Search All: This scans all text, the abstract, and all citation fields.  It combines each of the three searches indicated below.

Not all search systems permit all four of the above indicated domains of the search.  Various systems have different citation fields.  Occasionally a search of descriptors will actually result in a broader search than a search of the full text, even though rarely are more than 20 descriptors assigned to a report; that will happen if a human indexer realizes the report is relevant to a topic that is never mentioned in the report, and assigns it the descriptor for that topic. 

"Wildcards" and "Truncation Symbols"

Computers are literal.  If you search for "elementary schooling" they will ignore phrases like "elementary school," and "elementary schools" unless told to do otherwise.  This is not a problem when a human indexer assigns a descriptor from the search system thesaurus, because the thesaurus will exclude trivial variations of a term.  But it is a problem when searching titles, abstracts, and full text.  Many search tools allow you to use "wildcards" or "truncation symbols" to indicate the search should include all possible prefixes and/or suffixes of a specified root word.  The recognized symbol various among the search systems. 

First AidFirst Aid

The following are several fixes that may help when you encounter too few or too many hits.  Note that not all search tools permit all of these fixes, and each has its own requirements for how searches with multiple terms must be specified: 

Too few hits:

    1)Check the spelling and punctuation of your search term. 

    2) Use a "wildcard" (usually an asterisk) at the end of key words that can have multiple endings (such as school, schools, schooling, schooled) to search for all possible endings.

    3) Use synonyms and broader terms for the search.

    4) Use an "OR" search, specifying several synonyms simultaneously (some search tools allow you to just specify several synonyms, with a space between each; others require an “OR” between each word). 

    5) Check the few useful hits for references to other literature. For publications, check the descriptors for, and bibliography of, the hits.  For Web pages, check the higher level pages of the Web sites that you found (by truncating the URL shown in your browser window, one part at a time--parts are separated by a slash or period) or by exploring links to lower level pages at that Web site or links to other Web sites.

Too many hits:
    6) This is not a serious problem when using most web search engines because they list the hits in order of their apparent "relevancy" for the specified search; if the first 20 are not relevant, the search needs to be re-stated.  Some other search tools do not currently list the hits by relevancy, so if there are thousands of hits, you will want to re-run a narrower search. 

    7) Capitalize the initial letters of proper names (persons, places, or titles).

    8) Use synonyms and narrower terms for the search.

    9) Do an "AND" search, a "NOT" search, a "NEAR" search, or a "phrase search" (check that the search tool supports such a search and for how it should be specified). 

    10) Limit the search to the abstract, descriptor field, perhaps even the title field.

Other Search Lessons

This is the first of ten brief lessons on searching for scholarly and professional literature. The other lessons are indicated below.  For modest competency, each person should do Lessons S-2 and S-7, and the one most appropriate of Lessons S-3 to S-5.  Doctoral students should also do Lesson S-6.  The other Lessons will increase your productivity as a student and scholar, but are not essential for searching the literature. 

    Lesson S-2:   Web Search Engines--to get a "quick" take on a topic
    Lesson S-3:   ERIC--to find scholarly literature related to education
    Lesson S-4:   PsycINFO--to find scholarly literature in psychology
    Lesson S-5:   ABI/Inform--to find scholarly literature in human resource development
    Lesson S-6:   UMI Dissertation Abstracts--to find doctoral dissertations in all fields
    Lesson S-7:   Other Search Tools--for finding literature in the social science
    Lesson S-8:   Reference Librarians--for help when all else fails
    Lesson S-9:   Finding full text scholarly literature online
    Lesson S-10: Bibliographic databases for storing "finds" and printing reference citations

Last Update: June 26, 2000Link to the George Washington UniversitySend feedbackLink to Education Policy Page