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Systematic reviews

A brief overview of systematic reviews and resources to support producing one.

Introduction to building systematic searches

The search for a systematic review is based on the research question originally developed for the review. The goal of the search is to find all of the relevant studies, so it has to be comprehensive enough to capture all of the literature and to be performed in more than one source.

Key points to include in a search strategy

  • Use a mixture of title/abstract terms and subject heading terms
  • Use the Boolean operators AND and OR, and brackets, to combine the terms
  • Use truncation and phrases. Some searches may also use adjacency searching
  • Some searches may use a search filter (also called a hedge) to refine the search

The information below will guide you step by step as you build your systematic searches, and will cover each of the key points just mentioned in detail. The information covers just one approach to building systematic searches, and different people may do things slightly differently when building searches. Note that this information does have a health sciences focus but the principles can be applied to systematic searching in non-health disciplines, with variations as needed to suit the discipline.

Before you build a search

There are some things you should do before you start to build your systematic searches, including scoping searching, defining your research topic, checking for existing systematic reviews, and registering your review protocol. Watch this video or use the pdf document to see how to do these steps:

Make a preliminary search

The next step is to make a preliminary search, which can then be further developed into full systematic search strategies. Watch this video or use the pdf document to see how to do this:

Further developing your search

Once you've made a preliminary search, you next need to further develop this by limiting your search terms to the title and abstract fields, and adding subject headings (e.g. MeSH) to your search. Watch this video or use the pdf document to see how to do this:

How to know when your search is good enough

Once you've built yourself a good structured search in one database with all the features of a systematic search you'll need to take some extra steps to consider it done. Watch this video or use the pdf document to see how to do this:

Final steps

The final steps in the systematic searching process include translating your search for other databases, running the searches, deduplicating, record keeping and reporting, and then moving on to screening. Watch this video or use the pdf documents to see how to do this:

More information on some of the points covered in the video and pdfs above is covered elsewhere in this guide:

The Post search phase page of this guide also has some extra information on deduplicationrecord keeping and reporting, and exporting to EndNote.

The Select studies (screening) page of this guide also has some extra information on the screening phase.

The Evidence Review Accelerator (TERA)

The document above 'How to translate a PubMed (or MEDLINE Ovid) search' refers to The Evidence Review Accelerator (TERA), which contains the Polyglot tool to assist with translating searches. TERA is the new website replacing the Systematic Review Accelerator (SRA) which is being retired at the end of October 2025.

TERA works a little differently to the SRA. Here are some points to note:

  • To use TERA, you'll need to create a free account.
  • TERA is project-based, so you'll be prompted to create your first, free project. If you wish to create and retain multiple projects you'll need to subscribe, but it is possible to use your one free project and re-use the various tools as many times as you like. If you are regularly involved with evidence synthesis projects consider subscribing, to both retain your data and support the developers of TERA.
  • If you use a tool and would like your data to be saved for the next time you use TERA, make sure you click 'save progress' or 'save'. If there's no 'save' option you should make sure you capture any data you need before closing TERA (by exporting for example).
  • To re-use a tool that you have used before in your one free project, you may need to click 'clear' to clear any data currently showing in the tool.
  • The Polyglot tool which was previously available in the Systematic Review Accelerator is available in TERA. Due to the popularity of this tool however it has also been made available without a login at Polyglot.
     

Search filters

For some searches it will be appropriate to use a search filter (also called a hedge) to further refine the search. Most commonly this is done to limit search results to a particular study design, e.g. randomised controlled trials, but there are filters to limit results in other ways, e.g. to a subject area, to a geographic region, a particular condition etc. Filters are sets of search terms that have been developed by experts to refine a search in a particular way. The best filters have been validated. i.e. tested empirically to ensure they perform well and reliably retrieve relevant papers.

Resources for search filters:

Identifying and using filters appropriately can be a complex task. We'd recommend contacting our Librarian team who can help to get the best results for you in the quickest time.

Searching guides

Lefebvre C, Glanville J, Briscoe S, Featherstone R, Littlewood A, Marshall C et al. Searching for and selecting studies. In: Higgins J, Thomas J, Chandler J, Cumpston M, Li T, Page MJ et al, editors. Cochrane handbook for systematic reviews of interventions, Cochrane; 2022.

Lefebvre C, Glanville J, Briscoe S, Featherstone R, Littlewood A, Marshall C et al. Technical supplement to Chapter 4: Searching for and selecting studies. In: Higgins J, Thomas J, Chandler J, Cumpston M, Li T, Page MJ et al, editors. Cochrane handbook for systematic reviews of interventions, Cochrane; 2022.

Pettigrew M, Roberts H. Systematic reviews in the social sciences: a practical guide. Malden (MA): Blackwell Publishing; 2006. Chapter 4, How to find the studies: the literature search; p. 79-124. 

Kugley S, Wade A, Thomas J, Mahood Q, Jørgensen AMK, Hammerstrøm, et al. Searching for studies: a guide to information retrieval for Campbell systematic reviews. Campbell Syst Rev. 2017;13(1):1-73.

See section 3 'Conducting a search' in: Pullin AS, Frampton GK, Livoreil B, Petrokofsky G, editors. Guidelines and standards for evidence synthesis in environmental management, Collaboration for Environmental Evidence; 2022.

Basic and advanced searching

The information above will show you how to build systematic searches step by step and focusses on the essential techniques relevant to that process. If you'd like to learn more about database searching more generally the following resources may be something you'd like to explore:

Find quality information. This is UQ Library's more general guide to searching for information. Many of the concepts apply to systematic searching. Visit support and further resources for more resources including an interactive tutorial on advanced literature searching.