Systematic searching for literature reviews

Steps to a literature review

Step 1 - Formulate research question

• Clearly describe the research question, with relevant inclusion and exclusion criteria.
• To "translate" your research question into search terms you need to find key terms. A useful tip is to look at relevant research papers, and look at the words and phrases used there.

Step 2  - Find search terms and create a block search

• Depending on your research question, many databases may be relevant to search. For a comprehensive and systematic literature review it is recommended to search more than one database.
• For most databases you can find a thesaurus- a dictionary of predefined concepts.  In PubMed you can use MeSH terms, and in Embase you can use Emtree terms. Find more useful tips on our ... (hitta sökord-sidan)
• If you can't find relevant thesaurus terms for all your keywords, add them as free text words or search for them in Title/abstract field .
• Combine thesarus terms and keywords in a block search. (Learn more at...)Block search video

Step 3 - Evaluate your search result

• If you get to many results, you many have to narrow down your search strategy. This can be done by altering search terms, or adding filters for study design or publication date, population age group etc.
• If you find very few results, you may have to broaden the search strategy bu using broader terms. Make sure your combination of terms is not too narrow, so you miss important papers.
• A sensitivity test can be performed, by using a set of highly relevant key papers. If they are included in your search (add name of first author to your search strategy) the search will retrieve similar relevant papers.
• When you have a relevant number of results, you can start the selection process. The full search result is used in a literature review. For useful tips on selection, see Tools for systematic reviews section.
  
  
  

Illustration of sensitivity and precision (specificity) in systematic searching. From University Library of Toronto.

 Step 4 - Document your search strategy

• The search strategy is an important part of the method section in your literature review. It should be summarized in the method section, with the full search strategy available e. g. as an appendix or supplementary material. 
• Report all searches in all databases, give the date and any details on filters used.
• Here is an example of how a search strategy from PubMed can be documented:
  
  
  
  

Recommended reading on how to do a literature review