Before diving into a systematic review, it’s important to do a scoping search.
This provides an overview of the literature on an area of interest, and enables you to check if any systematic reviews have already been completed on your subject, and if conducting your own review is justified.
Scoping searches do not have to be as in-depth as the main searches you will perform later in the systematic review process. You will not have to search all of the available databases or resources, and a couple of sources will be enough to give you a feel for the topic.
It’s not uncommon for scoping reviews to evolve into formal systematic reviews in their own right.
Once you have identified a topic that interests you, it is important to see if a systematic review has already been carried out in this area. Below are some resources containing systematic reviews in various fields and can be a good place to start:
PROSPERO – prospective register of systematic reviews. Contains reviews that are currently being undertaken
Cochrane Database of Systematic Reviews – database for systematic reviews including protocols in health care
Campbell Systematic Reviews – publishes systematic reviews in the area of Social Welfare, Disability, Education, International Development, Crime and Justice, Training, Knowledge Translation and Implementation, and Business and Management
Clinical Psychology Review - publishes substantive reviews of topics relevant to clinical psychology
If you discover that the review you wanted to carry out has already been conducted don’t be disheartened. Consider some of the following:
Is the review exactly the same as your question?
Are the primary outcomes the same?
If it is not recent, can an argument be made to update it?
Has there been new research published?
If there is too much overlap or if carrying out the same review cannot be justified, you will need to refocus or adapt your review question.
When using databases for scoping searches you can apply some of these techniques:
Natural and academic language
Use a mixture of natural and academic language as these will appear in the title and abstracts of papers. For example, teenager has a lot of synonyms so a variety of alternative words can be used including teen, young person, young adult, adolescents, adolescence etc.
Subject headings
Subject headings are umbrella terms used by some databases to describe content or information. Articles are assigned a number of subject headings by indexers on behalf of the databases. It is a great method of searching for relevant literature related to your topic.
Phrase searching
Most databases use double quotation marks (“…”) to search for phrases. This is useful when you want to find results where the words appear together to make up a phrase, for example, "cognitive behavioural therapy" or “heart attack”.
Truncation
Many databases use the asterisk (*) as a truncation command. When used at the end of a keyword, it will instruct the database to search the root of the word and retrieve results with various endings, for example, disease* will find disease, diseases and diseased. Using truncation can be useful when searching for plurals.
Your subject librarian can help you with syntax and information on advanced searching for systematic reviews will be detailed in Step 3.
Completing a scoping search will give you an idea of the number of studies in your subject area.
Ensure that you read through the literature found by your scoping search. If you do find that a systematic review has already been published on your subject, you can console yourself with the knowledge that at least you discovered this at an early stage, rather than being deep into writing up your systematic review for publication.
Carefully read the titles and abstracts of your scoping search results, as these may provide you with additional search terms being used by other academics and researchers, which you can note down and include in your main searches.