The de-duplication of records from different databases will result in a reduced number of records. You now have to read the title and abstract of these records and apply your inclusion and exclusion criteria (established previously in your protocol). If the information in the title and abstract is not enough, you should check the full text of the paper. Use our Interlending service to place requests for any papers not covered by institutional subscriptions (papers are often supplied very quickly).
You might find it helpful to use a tool such as Covidence to support this screening process.
Once you know which are the included studies for your systematic review, you have to appraise the quality of these studies. You should be aware that not all the published studies will have a sufficiently rigorous methodology to avoid biased results. The links at the bottom of this page include checklists for different types of studies, to help you with this task.
Having done this, you will need to pull the findings together. This evidence synthesis involves the development of techniques to combine the outcomes of multiple sources in a narrative or statistical way.
Guidance for undertaking reviews in health care can be found in the below-listed chapters of:
Centre for Reviews and Dissemination. (2009). Systematic Reviews: CRD’s guidance for undertaking reviews in health care. York: CRD, University of York.