Google Scholar’s role in a systematised literature review process is slightly controversial.
As discussed previously Google Scholar is not recommended as a replacement for searching across multiple databases.
It can be used in addition to the databases as it a very effective search tool and is increasingly used in systematised reviews within a variety of fields. However if you decide to include Google Scholar, make sure you are transparent about how you used it and address any methodological points that may arise from its application. An advantage of using Scholar is that you may find additional grey literature (such as reports and policy documents) that are relevant for your research question.
Before you start to think about writing your review, you will need to use citation chasing and you may also need to use grey literature such as government reports or other official reports, this can be found in legislation and key policy documents on the subject guides and specialist websites.
Grey literature refers to literature which has not been formally/commercially published. This is particularly useful for reviews as it can identify literature which is outside 'publication bias'.
Grey literature includes academic papers, including theses and dissertations, research and committee reports, government reports, conference papers, and ongoing research. There is no single database that covers all types of grey literature, so you will need to consider what types of grey literature are most relevant to your review. You should also keep a record of which sites you have searched and how you have searched them, so that this can be reported.
Another useful way of finding relevant material is to check the reference list of articles which are to be included in the review to see if additional material can be located.
Scopus and Web of Science facilitate citation searching. This enables you to link through to publications which have cited a particular article which again can be a useful way of identifying additional material.
Reference list checking and citation searching facilitate chain searching which is going backwards (checking reference lists) and forwards (checking citing literature) in the research chain to identify other relevant literature.
For example in Scopus, after you have run your search, you can select the 'Cited by' field (to the far right of each record), this details the number of publications which have cited that particular document. Clicking on the number enables you to see the documents indexed by Scopus that have cited that item.
