"A systematic review is an academic research paper that uses a method called ‘evidence synthesis’, which can include meta-analysis, to look for answers to a pre-defined question. The purpose of a systematic review is to sum up the best available research on that specific question. Reviews can also show when there has not been enough research carried out, and where more research is needed" -- Campbell Collaboration
Article helpful for considering the best type of review for your study: Grant, M.J. and Booth, A. (2009), A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26: 91-108. https://doi.org/10.1111/j.1471-1842.2009.00848.x
Rapid review: uses systematic review methods to typically answer practical or policy questions in a time-constrained study
Scoping review: identifies the nature and extent of research evidence
Systematic review: systematically searches for, appraises, and synthesizes research evidence, adhering to guidelines
Umbrella review: compiles evidence from multiple reviews
Meta-analysis: This term is used in some fields as shorthand for a systematic review, but is an analytical approach that can be used with a variety of review types
The participation of a librarian on a research team is recommended or required by Cochrane, Campbell Collaboration, and the National Academies of Sciences, Engineering, and Medicine.