Specify study characteristics (e.g., PICOS, length of follow-up) and report characteristics (e.g., years considered, language, publication status) used as criteria for eligibility, giving rationale.
Think about criteria that will be used to select articles for your literature review based on your research question. These are commonly known as inclusion criteria and exclusion criteria. Be aware that you may introduce bias into the final review if these are not used thoughtfully.
According to the PRISMA checklist (item 6), authors should "specify study characteristics (e.g., PICOS, length of follow-up) and report characteristics (e.g., years considered, language, publication status) used as criteria for eligibility, giving rationale"