Once you've finalized your protocol, it's time to actually run your search. Once you've got your list of all results, you'll need to refine it by eliminating duplicates found between databases and screening studies to see if they meet your inclusion-exclusion criteria. It will be easiest to handle all of these results by exporting them to a citation manager. For more information on citation managers, refer to this guide. Among other things, a citation manager will allow you to easily identify and eliminate duplicates.
Once you have the results of your search, you will need to assess which items are relevant. Using your exclusion-inclusion criteria, review the titles and abstracts of your articles (or equivalent sections of gray literature) to make sure they are appropriate. Remove any that do not fall within the scope of your study, but be sure to document each item you remove from the results and your reasons for removing them. This ensures transparency in your selection process.
Once you've eliminated the items that obviously do not meet your inclusion criteria, you can begin to review the full-text of the remaining items.Then you can assess each item individually to determine whether it belongs in the final review. Importantly you must have at least two screeners independently assessing the results. You cannot do this process alone, as a properly conducted systematic review requires at least two independent assessments of each item's relevance, ideally with a third party to settle any disagreements. Once again, make sure that you carefully document each item you choose to exclude along with your reasons for exclusion.
This flowchart illustrates the screening process according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses), an internationally recognized set of guidelines for conducting systematic reviews.
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and MetaAnalyses: The PRISMA Statement. PLoS Med 6(7): e1000097. doi:10.1371/journal.pmed1000097
There are tools available online that you can use to organize and document your screening process.
Exporting Citations from Databases into Rayyan: For systematic reviews, it is recommended to export all of your results into a citation manager, de-duplicating your results, and then exporting from your citation manager in RIS format.