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Writing a Literature Review: Search the Literature

Help guide to literature review writing

KEY DATABASES TO USE

 

Search Strategy

A good literature review requires a comprehensive literature search, identifying all relevant research articles that best addresses your research question. It is important to structure your literature search systematically; clearly identify the scope before you begin and keep in mind the quality and relevance of the literature as you proceed.

PICO

Begin your search strategy by using the PICO framework below:

Structuring your question will clarify the search and identify keywords or search terms that will assist with your search.When conducting a search within a large database your search terms should be closely related to the components of your PICO question. For more information see the Tutorial on the right.

Example

You want to conduct a literature review that asks the question:

For an adult with lower back pain, is exercise or resting a more effective treatment?

P -  Adult with lower back pain

 -  Exercise

C -  Rest

O -  Relief of lower back pain

Using Synonyms

When conducting a systematic search for a literature review it is best to find all the synonyms you can on your keywords, such as lower back pain, lower backache

Join the synonyms together using OR eg. lower back pain OR lower backache

Joining Concepts Together for the Database Searching

Use AND to join the main concepts together

lower back pain OR lower backache

AND

exercise OR physical activity

Filters

Using the Limits or Filters within the databases helps define the scope of the literature review - for example is the focus on children or all recent literature that has been published in the last 5 years.

For the above example a limit to "All Adults" can be used.

Build a Search using MeSH

MeSH is the National Library of Medicine's controlled vocabulary thesaurus. Headings within the thesaurus are arranged in a hierarchical structure known as a "tree" that enables searches to be conducted at various levels of specificity. MeSH thesaurus can help find words used by indexers for medical concepts. This thesaurus works in the background of Medline by linking synonym.

EBSCO Medline Search Example

Where to Search?

Conducting a thorough search to identify relevant studies is a key factor in minimizing bias in the review process. The search process should be as transparent as possible and documented in a way that enables it to be evaluated and reproduced.  It is best to search multiple databases when looking for research and to also document how you conduct your search in the Methods section of your literature review.

  • Searching electronic databases
    • Medline
    • Informit (Australian Health Databases)
    • CINAHL
    • PsychInfo
    • ScienceDirect
  • Citation searching
    • Scanning reference lists of relevant studies
  • Contacting study authors, experts, manufacturers, and other organisations
  • Searching relevant Internet resources
  • Searching Google Scholar to check "Cited by"
  • Grey Literature

AI for Research

AI tools are becoming available to assist with searching the literature. Some things to keep in mind when using these tools are:

  • Bias - they only know what they know
  • Transparency - where is the data they search coming from?
  • Research integrity and ethics - consider this in the results you find
  • Integrity of the information (reproducibility, citation)
  • Peer review - can you check the peer review process of the literature found

AI Tools do have advantages as well. 

  • AI tools can streamline the publication process
  • They can speed up the review process
  • Improve inclusivity and accessibility (e.g., equity in publication through translation of works, reduction in costs)

Some tools useful for research are:

Write it Up!
Search strategies are often included as an appendix to a literature review and should give enough detail for someone else to reproduce the same or similar results. Your search strategy should include:
  • how you searched (e.g. keywords and/or subjects)
  • search terms used (e.g. words and phrases)
  • search techniques used (e.g. nesting, truncation, etc.)
  • how you combined searches (e.g. AND / OR / NOT)

Source - http://research.library.gsu.edu/c.php?g=115595&p=754153

What are you going to include and exclude?

What articles you include and exclude is determined by the goals, coverage  and context of the research question. This inclusion / exclusion criteria must be made explicit in the Literature Review. For example, you might include or exclude according to:

1. The right Type of study for your review question? e.g. Randomized Control Trials; case studies,cohort studies

2. Publication timeframe e.g. 2006-2016

3. Population or patient group 

4. Significant sample size

5. Published in English

 

https://s3.amazonaws.com/libapps/accounts/38818/images/PRISMA_Flow_chart.PNGThe PRISMA (Preferred Reporting Items for Systematic Review and Meta-analysis) flow diagram has been developed specifically for Systematic Reviews. It allows the author to visually depict what articles have been identified and how articles have been screened for eligibility. You can adapt this flow chart to help you depict and articulate how you have arrived at the final set of articles to review.

 

 

https://s3.amazonaws.com/libapps/accounts/38818/images/PRISMA_Checklist.PNGThe PRISMA Statement is the gold standard for conducting and reporting a systematic reviews. Along with the flow chart, the site also provides a helpful checklist for developing a Protocol  which sets out what databases have been searched, the inclusion and exclusion criteria, search terms defined, method to analyze the data etc. It is a tool to provide transparency to your literature review and may be required when submitting your article for publication. Again, it has been designed for Systematic reviews, but you can adapt the checklist to your own literature review. 

Moher, D., Shamseer, L., Clarke, M., Ghersi, D., Liberati, A., Petticrew, M., & ... Stewart, L. A. (2015). Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement. Systematic Reviews, 41. doi:10.1186/2046-4053-4-1

 

To generate a PRISMA flow diagram from a csv file use this handy tool created by Neal R Haddaway and Luke A McGuinness

Flow charts can be referenced using the following citation:

Neal R Haddaway, Luke A McGuinness. (2020). PRISMA2020: R package and ShinyApp for producing PRISMA 2020 compliant flow diagrams (Version 0.0.1). Zenodo. http://doi.org/10.5281/zenodo.4287835

KEY TIP

PICO Tutorial

Conducting a Literature Review Tutorial