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Conducting a Literature Review: 3. Search the Literature

A guide to the basic steps of doing a literature review.

Getting Started

  • Determine your scope - Use filters/limits (e.g. demographics, language, date range, study type, geographic region) to reduce the number of articles you need to review.
  • Come up with initial keywords for the concepts of your question. 
  • Start with the most recent material and work backwards. This allows you to not only find good recent studies but also points out that seminal reference everyone else quotes.
  • Repeat the search in other databases.  Remember to evaluate as you search - simply gathering isn't the goal, you want to find sources you can use.
  • Assess whether you have enough literature or if you need to choose another topic.

Focusing Your Topic

Determine the scope of your literature search.  The more precise your topic is, the easier it will be to complete a literature review. 

A literature review of: Is....
alcohol consumption by students too broad and will lead to many results.
beer drinking by U.S. college students in the 1990's still a broad topic, but has a geographic and temporal focus that will help narrow the scope of the research and the literature review.

 

Also consider:

  • What exactly will you cover in your review?
  • How comprehensive will it be?
  • How long? About how many citations will you use?
  • How detailed? Will it be a review of ALL relevant material or will the scope be limited to more recent material, e.g., the last five years?
  • Are you focusing on methodological approaches; on theoretical issues; on qualitative or quantitative research?
  • Will you broaden your search to seek literature in related disciplines?
  • Will you confine your reviewed material to English language only or will you include research in other languages too?

Boolean Operators

Boolean Operators:  Boolean logic is a system that allows a searcher to set relationships between keywords or concepts when searching. The most commonly used Boolean commands are AND, OR, and NOT.  Using these operators can make your searches more precise and save time.

AND NARROWS: 
Tells the database that you only want articles that contain ALL of the search terms

OR EXPANDS: 
Tells the database that you want all articles that contain EITHER of the terms

NOT EXCLUDES: 
Tells the database that you do not want any articles that contain a certain term

JOINING NARROWS: 
(Smoking OR Nicotine) AND cancer
Tells the database that you want articles with EITHER of two terms AND another

Set Filters or Limits

Databases usually allow you to limit or filter your search results in various ways. These may include:

  • language
  • type of publication (case study, clinical trials, review articles)
  • sex
  • age groups
  • date published
  • peer-reviewed

Advanced Search Techniques

Most databases use the symbol * or # for truncation or wildcard symbols. Use the database's Help tab for verification of the correct symbol.

Truncation Symbol:  Uses root of the word…

Example:  pharm*

Finds pharmacology, pharmacy, pharmaceutical, etc.

Wildcard Symbol:  Allows for multiple spellings of a word...

Example: sul*ur

Finds sulphur and sulfur

Exact Phrase: Use quotation marks to search for an exact phrase.

Example:  "persian cat"

Finds information on cats that are the Persian breed, not just cats in relation to anything Persian.

Proximity operators:  Proximity (or adjacency) operators allow you to search by phrase or with two or more words in relation to one another. Use the database's Help tab for to verify what symbol to use.

Near (n): if it does not matter which word appears first.

Example: Prozac n3 adverse effects

Finds Prozac within three words of adverse effects

With (w): if your terms must be in the same order in which they are entered.

Example: physical w1 therapy

Finds records where the word physical is listed first, followed by the word therapy, and where no more than one word separates the two terms.

Stop words:  Stop words are very common words that are automatically ignored by most databases.

Examples:  and, if, or, the, a, for, to, an, as, by

Use quotation marks if you need to search for a term that has a stop word in it, such as "Out of Africa" or "The Who".

Tips

You know you've exhausted a literature review when you see the same articles and books over and over again as you search - in databases, in reference lists, etc. Then you know it's time to begin reading and synthesizing all that you've collected.