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Conducting a Literature Review

Selecting Sources to Search

A good literature review should be as comprehensive as necessary to identify all of the major works and debates on your research subject.  

Subject-specific Databases - search in databases specific to your discipline of study to find more sources in your field. For example, Sociological Abstracts specializes in Sociology and will have more coverage of the sociology literature than an interdisciplinary, all-purpose database such as ProQuest.  You should also search in more than one database/catalog since no one search tool covers everything.  For example, if your topic involves education, consider also searching an education database, such as ERIC.

Here are ideas about finding places to search.

Databases A-Z - Once you've identified disciplines or information types, consult the Databases A-Z list by subject.  

Google Scholar -  also search for your topic in Google Scholar.  If you have a relevant source, consider searching the title in Google Scholar and using the “Cited By” link and the “Related Articles” to locate more literature.  

Library Catalog - The Library Catalog also searches a variety of databases for books and journal articles at once. However, it does not search everything, so be sure to also look at disciplinary databases

Database Searching Tips

Keywords:

The search terms or keywords you use to search are what determine the results you get.  

1. Express your topic in a topic sentence

2. Generate keyword search terms by identifying the main ideas or concepts within that topic sentence:

3. Expand your search terms by brainstorming related terms or synonyms that describe your main ideas

 

Boolean Operators or Combine Search Terms; AND, OR, NOT

Boolean logic is a building block of many computer applications and is an important concept in database searching.  Using the correct Boolean operator can make all the difference in a successful search.For example, if your search terms are Shingles and vaccines and aged.

  • AND searches find all of the search terms.  For example, searching on shingles AND vaccine AND aged returns only results that contain all three search terms.  Very limited results.
  • OR searches find one term or the other.  Searching on Shingles OR Varicella-Zoster OR chickenpox returns all items that contain any of the three search terms.  Returns a large number of results.
  • NOT eliminates items that contain the specified term.  Searching on Shingles NOT chickenpox returns items that are about Shingles, but will specifically NOT return items that contain the word chickenpox.  This is a way to fine-tune results. Note:  sometimes AND NOT is used; serves the same function as NOT.

Using Boolean Search with Exact Phrases:

If you're searching for a phrase rather than just a single word, you can group the words together with quotation marks.  Searching on "Varicella Zoster" will return only items with that exact phrase.  

Phrase Searching:

If you are searching for a phrase, keep in mind that not all databases will search multiple words automatically as a phrase.  Check the database Help pages to be sure how that database handles multiple works.

  • Some assume that words typed next to each other should be searched as phrases.
  • Others automatically put a Boolean AND between your search terms, requiring that all the words be present, but not necessarily adjacent to each other.
  • Some databases such as PubMed (and Google) use " " around multiple words to designate a phrase search.  For example:  "Varicella-Zoster Virus"

When to use parentheses:

Think of your search in concepts, then put those concepts inside parentheses.  Different databases have different rules about combining searches.  To make sure you get the search you want, use parentheses - every database follows those rules.

Truncation:

Using truncation symbols allows you to expand your results by including various endings for a search term.  Most databases will designate a non-alphabetical symbol -- like  ! , *, or ? -- as a truncation symbol; check the database Help screens to find out the specific symbol.             PubMed uses an Asterisk ( * ).  Using the truncation symbol at the end of the root word will bring back results that include any ending of that root word.  For example, if the truncation symbol was a ? , then:

  • child* = child, child's, children, childish, childlike, childhood
  • transplant*  = transplants, transplantation, transplanted

Cited Reference Searching

Cited Reference searching is the ability to search the list of references (or footnotes) found in journal articles, books, dissertations, websites, etc. It is based on the premise that you have a scholarly work in-hand that you really like and you want to see who else has used that work in their research - therefore, have included it in their list of references (or footnotes). Typically, cited reference searching involves looking for works by a particular author or for a specific piece. The best database for cited reference searching are Scopus and Google Scholar.

Save Your Search

Save Your Search Results

Save copies of the useful records you find and where possible save a copy of your search strategy. This will ensure that you don’t have to repeat work.

Save the articles you find:

Always save or print the useful article records you find. Most databases give you a few options, such as:

  • save – usually as a text file or an RIS file
  • print
  • email
  • direct export to reference software such as Zotero.

Generally you will not be able to download the full text of the documents directly from the database. In many databases you will have to follow the "full text" links. If the Library has a subscription, you will be able to download the article.

Save your search strategy

The database may have a free personal account feature that allows you to save a copy of your search strategy. Saving your strategy means your search can be re-run without you having to re-enter details.

Search Activity Log

Be sure to keep a search activity log, which documents where you searched, search terms and number of results. This can be done very easily in Excel or Sheets:

Search log

Beyond the HMSOM Library

InterLibrary Loan (ILL)

Interlibrary services are available to students, faculty, administrators, and staff of HMSOM. We can help you borrow articles or book chapters not held by the HMSOM through the use of Interlibrary Loan (ILL) to get it. Articles and chapters are scanned and sent electronically.

Databases

HCUPnet is a free, on-line query system based on data from the Healthcare Cost and Utilization Project (HCUP). The system provides health care statistics and information for hospital inpatient, emergency department, and ambulatory settings, as well as population-based health care data on counties

PubMed comprises more than 22 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

International coverage of journal articles, conference proceedings, selected web sites, and patents in the sciences, social sciences, and humanities; provides citation tracking for 1996+ (select coverage for earlier periods) and cited reference searches back to 1970.

Subject Headings

Subject Headings:

Subject Headings, also called descriptors, these terms are assigned to items to describe their content, or what they are about. Subject headings often facilitate more precise searching as they eliminate the need to search multiple phrases and synonyms for the same concept.  Look for subject headings on items in the library catalog and in databases of journal articles.  Many databases also provide a thesaurus, or index, of the subject headings used

 MeSH:

Medical Subject Headings (MeSH) is a comprehensive controlled vocabulary for the purpose of indexing journal articles and books in the life sciences. It serves as a thesaurus that facilitates searching. Created and updated by the United States National Library of Medicine (NLM), it is used by the PubMed article database and by NLM's catalog of book holdings. The 2021 Medical Subject Headings are available at: https://meshb.nlm.nih.gov/search.

In PubMed, every journal article is indexed with about 10–15 subject headings, subheadings and supplementary concept records, with some of them designated as major and marked with an asterisk, indicating the article's major topics. When performing a MEDLINE search via PubMed, entry terms are automatically translated into (i.e. mapped to) the corresponding descriptors with a good degree of reliability; it is recommended to check the 'Details tab' in PubMed to see how a search formulation was translated. 

Author Search

Author Search - many researchers will write about the same topic for their entire career. Searching by an author's name in a subject database and/or Google Scholar  PubMed, Scopus may garner additional relevant articles related to your topic.

Bibliography Mining

Bibliography Mining - use the list of works cited from a relevant source to locate additional related sources.  This is a way to look for relevant sources published prior to the one in hand.  A database may have a direct link to all the works cited, such as the example below; otherwise, you may need to look at each work cited manually.