Research Support

Brown University, Center for Evidence Synthesis in Health (2018) The steps in a systematic review.  Available at: https://youtu.be/-FQSsnaAtOU (Accessed: 29 June 2021).

Systematic reviews seek to collate evidence that fits pre-specified eligibility criteria in order to answer a specific research question. They aim to minimize bias by using explicit, systematic methods documented in advance with a protocol (Chandler et al., 2019 in the Cochrane Handbook).

A minimum of 2 people and a long timescale are required for registered systematic reviews.  However, the same principles can be applied to more restricted forms of review, e.g. a rapid review or a scoping review, undertaken by one person or over a short timescale. 

Rapid review: can be used to ascertain the extent to which an intervention is based on evidence.

Scoping review: often used to explore the volume of evidence on a topic and viability of a research question.

Further reading:

Sarri G, Patorno E, Yuan H, Guo, J., Bennett, D., Wen, X., Zulio, A.R., Largent, J., Panaccio, M., Gokhale, M., Moga, D.C., Ali, M.S. and Debray, T.P.A. (2022) 'Framework for the synthesis of non-randomised studies and randomised controlled trials: a guidance on conducting a systematic review and meta-analysis for healthcare decision making', BMJ Evidence-Based Medicine,27, pp.109-119. Available at: https://ebm.bmj.com/content/27/2/109 (Accessed: 28 March 2022).

Stewart, L., Moher, D. & Shekelle, P. (2012) 'Why prospective registration of systematic reviews makes sense', Systematic Reviews, 1(7).  doi: 10.1186/2046-4053-1-7

Formulating your question

The first step in any review is to ascertain the appropriate question. 

The PICO and related tools are designed to assist with topic mapping and to ensure resulting research questions are robust. These tools consider multiple aspects and give focus to your planning.  For example, PICO focuses on the population you are trying to help, the relevant intervention and desired outcome.

See our guide to PICO and related tools:

Scoping the evidence

A scoping study is generally undertaken to gain awareness of the existing research literature, or evidence, on the topic and to ascertain the viability of the research question or hypothesis.

The scoping study informs the search strategy which will be implemented in the review:

• The topic elements to be included.
• All of the appropriate search terms representing each element.
• Research studies and other types of item which will be analysed.
• The bibliographic resources and other sources to be searched or consulted.
• Additional criteria determining the selection of materials for review.

The scoping study is also an opportunity to confirm that a systematic review on your question does not already exist, and that none are in preparation. As well as the bibliographic databases, check the collaboration collections:

Health-related topic?

Explore searches and filters developed by others:

Further reading:

Cooper, C., Booth, A., Varley-Campbell, J., Britten, N. and Garside, R. (2018) 'Defining the process to literature searching in systematic reviews: a literature review of guidance and supporting studies', BMC Medical Research Methodology, 18(1), pp. 85.

Gusenbauer, M. and Haddaway, N. R. (2020) 'Which academic search systems are suitable for systematic reviews or meta‐analyses? Evaluating retrieval qualities of Google Scholar, PubMed, and 26 other resources', Research Synthesis Methods, 11(2), pp. 181-217.

Munn, Z., Peters, M.D.J., Stern, C., Tufanaru, C., McArthur, A. and Aromataris, E. (2018) 'Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach', BMC Medical Research Methodology, 18(1), p. 143.

Registering your review at an early stage minimises the chances of duplication and enables contact with others interested in the topic. 

Registration sites include:

Searching the databases

Look for research studies and other evidence sources on your question by searching the most appropriate bibliographic databases for the topic. See Suggested Resources for commonly used resources. Your academic librarian can advise on the most relevant resources for your question.

Apply the search terms and generic selection criteria, e.g. published 2017-2022, from your search strategy (see Scoping the evidence above).  Be consistent with your terms across resources but also adjust your use of database features to ensure the best use of that collection's functionality. Our series of A-Z database guides may be useful.

For example, selecting the 'textword' filter is standard practice but proximity searching (searching for words near or adjacent to each other) may not be offered by every database you select.

In some cases, searching by subject heading or thesaurus term will be the preferred method. For example, you can search CINAHL, MEDLINE and PubMed using Medical Subject Headings (MeSH) or apply the APA Thesaurus of Psychological Index Terms in APA PsycArticles.

Remember, your search should minimise bias where possible.  Your search terms should include alternative descriptors as well as your primary search term. Use Boolean operators - AND, OR and NOT to combine your search terms together. E.g. (dementia OR alzheimers) AND (community OR communities OR home OR citizenship)

Searching the databases - systematic literature searching

It's important to understand the basics of searching because for a systematic review, your search will have to be more sophisticated. There are some important differences between basic searches and more advanced and systematic searching. In systematic searching, the scope of the search, technicality, and methodical and structured approach distinguish it from traditional searches. At its core, every search query is constructed using Boolean logic (AND, OR, NOT) to specify the relationships between different terms and criteria. Virtually every search engine, whether it's a web search engine like Google or a database search engine like PubMed or Scopus, operates based on Boolean logic principles. By using Boolean operators such as AND, OR, and NOT, users can refine their search queries to retrieve more relevant and targeted results. Visit our Systematic Literature Searching guide to learn more and develop your skills

Thinking ahead - reporting the details

You will be documenting your search strategy and number of results in your report.  Taking notes at the end of each search session of the searches run and the number of results generated will facilitate your report.  The 'Search History' feature, if available, will summarise this for you.

Finding other sources of evidence - grey literature

Also apply your search terms to relevant grey literature sources. Common sources include government documents, regulatory reports, clinical trials, conference papers, theses and social media posts. 

Grey literature sources are not collected and organised in the same way as published journal literature so flexibility is required.  Website searching, hand searching of known publications, manual analysis of reference lists and, in some cases, contact with authors/subject specialists can all apply.

Commonly used bibliographic and grey literature sources are listed on our Suggested sources page. 

Further reading:

Paez, A. (2017) 'Gray literature: An important resource in systematic reviews', Journal of Evidence Based Medicine, 10, pp. 233– 240. doi: 10.1111/jebm.12266

Stansfield, C., Dickson, K. and Bangpan, M. (2016) 'Exploring issues in the conduct of website searching and other online sources for systematic reviews: how can we be systematic?', Systematic Reviews, 5 (191). doi: 10.1186/s13643-016-0371-9

Screen database entries and other items for those which match the selection criteria in your search strategy. This will be a staged process looking at titles first, then abstracts.  The vast majority of results will be rejected at this stage.  The remaining items can then be viewed in full - until an exclusion criteria is met.

Keep notes of the numbers of items selected and rejected at each stage - this is required for PRISMA 2020 flow diagram, or equivalent.

Screening tools

There are many tools available to assist with the screening process. For example, if you are using EndNote to store all your source details, the 'Research Notes' feature can be extremely useful here.  However, many tools are available to automate this part of the process.

Please note: library staff are unable to offer support with using these products.

Once you have your confirmed list of studies, it's time to extract the data.  

For each study, note the title, methodology, selection criteria, conclusions and other desired details.  

Applying relevant critical appraisal tools will facilitate this process.

Please note: library staff are unable to offer support with using this product.

Complete your report in compliance with the PRISMA protocol and/or conditions set by other organisations, e.g. Cochrane or JBI