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Subject guides

Physiotherapy: Systematic Reviews

This is a subject guide to give students of Physiotherapy an overview of the different resources available at the University of Huddersfield.

Systematic Reviews

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What is a systematic review and do you really need to do one?

A systematic review is a very specific approach to searching for literature which seeks to find all studies which have been published and which meet the review's eligibility criteria.  A true systematic review should include clear objectives with eligibility criteria for inclusion; a methodology, which it should be possible to replicate; critical appraisal of the findings of included studies; and a systematic presentation and synthesis of the findings of the selected studies (Higgins & Green, 2011). If you are not sure whether you need to do a systematic review or just a literature review, here is a useful guide which will help you decide, produced by Lynn Kysh at the University of Southern California.

In the words of the Cochrane Handbook,

"A systematic review attempts to collate all empirical evidence that fits pre-specified eligibility criteria in order to answer a specific research question.  It uses explicit, systematic methods that are selected with a view to minimizing bias, thus providing more reliable findings from which conclusions can be drawn and decisions made"

Antman, 1992, Oxman1993 (cited in Higgins & Green, 2011, section 1.2.2).

Higgins, J.P.T. & Green, S. (Eds.). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Retrieved from: http://handbook.cochrane,org

There are more useful definitions of different types of systematic review on the Glasgow Caledonian University website

Running and recording your searches

At this stage in the process, good record keeping is vital.  You will need to keep an up to date and accurate list of searches run against keywords and how many results each line of your search strategy produced.  Because new articles are always being added to databases, always keep a record of the dates you ran your searches.  Because accuracy is so important, it is a good idea to write up your searches as you run them.

Some databases enable you to register your own account so that you can save searches to retrieve them later and also set up alerts to be informed of new articles which are added to the database which match your search criteria.  

If the database you're using has a Search History function like CINAHL, this will enable you to easily combine different lines of your search strategy. For more information on this functionality, see the CINAHL help pages.

Critical appraisal and synthesis of your results

Once you have decided which studies are to be included in your systematic review report, you will need to critically appraise their quality.  There are a number of tools available which will help you to do this, including:

You will also need to pull your findings together, or "synthesise" them.  You may choose to do this using narrative synthesis, if you are dealing with qualitative research or statistical synthesis, if you are dealing with quantitative research.  There are two chapters in York University's Centre for Reviews and Dissemination guidance for systematic reviews which will be of great help with this process:

Centre for Reviews and Dissemination. (2009). Systematic Reviews: CRD’s guidance for undertaking reviews in health care. York: CRD, University of York.

Writing and reporting your review

When writing up your research, there are a number of models you can use to guide your reporting process

  • PRISMA: PRISMA is used primarily for reporting on systematic reviews and meta-analyses. It's useful for lots of different types of research, but was designed primarily with randomised trials in mind.
  • MOOSE: Meta-analysis of observational studies in epidemiology (MOOSE). Please note, more information on MOOSE is available here, but is not part of library subscriptions

Your search strategy

Before you start searching you will need to develop a detailed search protocol.  Your search will need to aim for high sensitivity, in other words, it needs to be a very broad, comprehensive search which covers all possible terminology.  This will mean a corresponding low level of precision, or relevance.

Scoping the review in detail is crucial, for example what population is of interest and within that population what age group?  How far back in time do you need to go?  You will also need to identify all the databases and other sources of literature which are relevant to search, including grey literature.  At the scoping stage it is important to run preliminary searches to identify some key papers which are relevant to the review.

You will need to turn your question into a search strategy which uses both free text and thesaurus terms, having first ensured that you have read and understood any proposals or protocols which have been agreed for the review. You may find it helpful to use a tool to structure your search strategy such as PICO or SPIDER. 

It is a good idea for more than one person to be involved with drafting the search strategy and it should always be checked to ensure that it retrieves key papers which have already been identified at the scoping stage. The strategy can then be revised before the full search is run.  Once you have identified a strategy which works for one database, you can adapt it for other databases.

For help with search strategies, here are some useful links:

Managing your search results

To manage your results effectively, we recommend that you use a reliable reference manager such as RefWorks. As well as providing a good place to store your references and organise them thematically, RefWorks has a deduplication tool which will be invaluable to you as you will be using multiple databases to run your systematic review, so some duplication of results is inevitable.

You can set yourself up with a subscription to RefWorks - we recommend the Use login from my institution option.

More information and help on using RefWorks is available from our reference management guide.

Further help

Bryony Ramsden and Kate McGuinn are available to advise on search strategies for systematic reviews but, due to time constraints, are not currently able to take part in the systematic review process. If you need further help, the following links and information may be of assistance

Guides available online

  • The University of Oxford Bodleian Library has a subject guide about all aspects of systematic reviews
  • The University of York has published a free guide on systematic reviews that is available here.
  • Glasgow Caledonian has a website filled with useful information on carrying out a systematic review

Books in the library

Organisation websites

  • Cochrane - Cochrane's website has a wealth of information about systematic reviews and details of online and face to face training
  • Campbell Collaboration - Information and support for reviewers in the areas of Crime and Justice, Disability, Education, International Development, Knowledge Translation and Implementation, Nutrition and Social Welfare
  • Joanna Briggs Institute - an international not-for-profit, research and development centre at the University of Adelaide, South Australia