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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:

Before you build a search - systematic searching part 1 (YouTube, 14m 19s)

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:

Making a preliminary search - systematic searching part 2 (YouTube, 13m 32s)

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:

Further developing your search - systematic searching part 3 (YouTube, 10m 16s)

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:

How to know when you're done - systematic searching part 4 (YouTube, 21m 16s)

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:

Final steps - systematic searching part 5 (YouTube, 20m 5s)

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.

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 the UQ Librarians 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:

Advanced literature searching tutorials

Database searching information