Having completed the scoping process in Step 1 (see Getting Started section), you are now ready to start planning your search in more detail. At this stage, you will need to decide where and how you are going to search. The search strategy that you will develop will form an important part of your systematic review and needs to be clear and methodical so that it can be replicated in the future. Watch the video on how to create a search strategy and read through the information provided below. Next download the Full Search Planner Example and then create your own detailed search plan (to do this you need to complete the next section on your search planner that you saved in step 1)
Where to search?
As described below Library databases can be grouped into two different types. However, depending on your topic you might wish to search subject specialist databases first, but you will need to search the full range of databases to complete the Systematic Review. The EndNote de-duplicating process will keep the first references from the first database searched and remove any subsequent ones added from other databases.
Interdisciplinary bibliographic databases
These cover a wide range of subjects and will give you the bibliographic details of the item/article rather than the full text. However, if we have access to the full text, the 'Find at Newcastle' button next to each article will directly link to Library Search to identify whether we have the full text via another database. We have many databases that cover specific subjects, but only two main databases that cover all subjects: Scopus and Web of Science.
Why would you use interdisciplinary bibliographic databases?
Using databases such as Scopus and/or Web of Science allows you to broaden your search to find a range of peer-reviewed content that is out there related to your topic. They are also very useful if your research topic is interdisciplinary: e.g. the history of medicine, as well as for scoping your research to see what is out there already. If you decide to use both of these databases, you will find a lot of overlap. However when undertaking a systematic review, you will need to search both of these to catch the references which are unique in each database.
Subject specialist databases
Searching within a subject specialist database will immediately focus your search, helping you more easily identify key references, publications or authors within your discipline. You will also find references which are not covered by the interdisciplinary databases.
Subject specialist databases usually include more advanced searching features, such as the option to choose subject headings from a thesaurus, or use a controlled vocabulary. This allows you to search more successfully, using subject-specific terminology which may have a very different meaning in other disciplines.
To find out what subject specialist databases are suggested for your subject, go to your subject guide.
Using Google Scholar to find journal articles for systematic reviews comes with major warnings. It is certainly not sufficient to be used on its own to support systematic review searching and if it is used, it definitely needs to be used in conjunction with the Library databases already mentioned. It also may not be appropriate to use Google Scholar at all, as it is very hard to replicate the search with any accuracy. Unlike a database which has been indexed in a systematic way, Google will not reveal how its algorithms and rankings work and therefore, there is no certainty that the results that are generated one day will be generated another, even if the same keywords are inputted. As a result, Google Scholar may be used at the scoping search stage, but it is rarely used further on.
If researchers need to find grey literature using the internet, they often choose to use Google advanced search as they can have more control over the search and it can be more easily replicated. Please see the Finding Grey Literature tab for further details.
What is Grey Literature
Unpublished material is called grey literature and can contain lots of different types of documents, including conference proceedings, theses, government reports, technical reports, official documents and even blog posts, tweets etc. You would normally expect a systematic review search to include grey literature, so that you don’t just retrieve the research that has generated ‘positive results’ which would give your research a bias. For example, if an intervention / drug / treatment / method has seen positive results, authors are more likely to submit the research to a journal and it is also more likely to be accepted as it is seen as interesting. Less positive or notable results may not be published and therefore become classed as grey literature. However, this grey literature is still important to identify in order to get a balanced view and ensure that your research is systematic and not just a literature review.
If you are not sure whether you should be searching grey literature as part of your systematic review, then please discuss this with your supervisor. The scope could be to search only formally published literature but this must be made clear at the start.
Use the Grey Literature Guide to find out which sources you should be checking, linking you to our Guides on conference proceedings, theses and government reports.
Creating a successful search strategy
Full search planner
- Full Search Plan ExampleAn example of what a full search plan could look like. Please look at this before filling in 'the developing your search strategy section' of your own search planner.
Links to relevant resource guides, subjects guides and websites
