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Systematic reviews

Comprehensive searching

The process below outlines how to develop a comprehensive search strategy.

There are a range of resources that you can refer to for more information, such as the Systematic Review Toolbox.

For your project: 

  • consult with your supervisor and team for subject-specific expertise
  • consider booking a Research consultation for more tailored guidance on searching

Search steps

1) Environmental scanning

Mind map

Conduct a general search to get an idea of the amount of literature on the topic and the terminology in use.

Canvass other reviews or theses in the subject area to see what has been done and how they searched.

If you have identified key papers, check the reference lists. You can also check what papers have cited them.


2) Building your search

venn diagram with whale AND ship

Formulate your research question or topic. Consider any limits: study type, publication year, country etc.

Identify the key concepts and any alternative terms and subject headings for each concept. 

Look at relevant articles for their keywords and subject headings, or use database thesauri.


  • When developing a search strategy, it is best practice to use both keywords and subject headings
  • Keywords are terms that you or the author would use to describe a topic
  • Subject headings are assigned by databases from a standardised set of terms. They indicate the main concepts of an article
  • Subject headings are a powerful way to search as they capture articles with alternative terms you may not have considered. They are particularly important for medicine subject areas
  • Note that not all databases use subject headings, and headings differ across databases


3) Choosing databases

Journals are indexed in different databases, so you may need to search more than one.

Find databases by topic using the Library's Subject guides.

The number of databases you search depends on your topic and the type of review or research task.

Depending on your topic, you may also need to find other types of information that are not in databases e.g. policy documents, government reports, and other grey literature.

  • Using Google has its advantages and disadvantages depending on your topic
  • Google Scholar is useful as a complementary tool to academic databases. It can be used to find very recent papers or preprints, or for topics where there is not a lot of coverage in academic databases
  • Google Advanced Search can be used to find grey literature available online
  • When looking at information online, it is important to evaluate the resources found


4) Searching and iterating

Testing and searching workflow

Develop an initial search strategy in one database using keywords and subject headings. Combine terms using boolean operators and techniques such as truncation, phrase and proximity searching.

Review the search results - is it identifying relevant papers? Do you need to adjust your search terms?

Adapt your final search to other databases.

For help with your search strategy, request a Research consultation

  • Check your search results to see if known key papers are being retrieved
  • Make sure you have all relevant subject headings - check the headings of relevant papers
  • If there are key authors in the field - make sure their papers are being picked up
  • If you are getting a lot of irrelevant material - take a close look at the records to see what search terms are retrieving these. The terms may be too broad or have multiple meanings
  • Check for errors e.g. in spelling or search operators
  • Databases usually have their own subject headings so you will need to identify these
  • You can use subject headings found in one database as keywords in another
  • Multidisciplinary databases such as Scopus do not use subject headings and require keyword searching
  • Search fields and techniques e.g. proximity operators may differ across databases


5) Documenting your search

When you write your review, you will need to report your search strategy so that it can be reproduced, if needed.

Keep a record of what search terms you use, where you search and your final search strategy for each database used.

  • PRISMA and Cochrane offer guidance on how to report your search. You can also look for a review in your field and see how they have reported their search strategy.
  • Look for features in databases to save your searches. You can also set up a search alert to receive notification of new research.
  • EndNote, Excel and other reference tools can be used to help manage your search results. Consider using review tools such as Covidence or Rayyan to manage systematic reviews. See the Systematic Review Toolbox for software options.

Need help?

For quick questions, book an Expert on demand.

For more involved support, book a Research consultation.