Once you have defined your focused research question, and determined your inclusion and exclusion criteria, you now need to develop your search strategy to ensure all relevant literature is retrieved from a variety of sources.
In designing your search of the literature, you should consider:
It is useful to build a 'sample set' of relevant references before you develop your search strategy.
The 'sample set' of references will enable you to:
The 'sample set' may include:
The search strategy needs to include a detailed list of search terms for each concept to ensure all relevant studies are captured for the review. Search terms will be made up of keywords, or phrases, as well as database subject headings. Each database uses a different criteria to classify articles, so the subject headings will differ between each one.
To assist in identifying useful search terms:
You also need to consider the limits you intend to apply to your search. Searches of databases will provide options that include:
When using multiple databases you are likely to encounter a large volume of resources. During the search stage, you can continually adjust research questions, search terms and/or selection criteria in order to make sure you have a comprehensive body of references.
It is recommended that you test your search terms to determine if all the subject headings and words/phrases will return useful results. Test your search strategy in a key database. Does it retrieve any papers from your 'sample set' that are contained in that database? Are the results of the search relevant to your topic? What proportion are irrelevant? Identify any terms that are retrieving large numbers of irrelevant papers.
Now that you have completed the preparation for your systematic review, it is time to execute your search and analyse search results to determine the papers that will be included in your review.
It is essential that you thoroughly document your search process in enough detail to ensure that it can be reported correctly in the review. You may choose to create a spreadsheet to record the details of your searches, and to save your search histories - this requires setting up a free personal account in each database.
For each database search you conduct, you should record: