This guide provides an overview of the processes involved in finding and managing information sources for use in systematic reviews and meta-analyses.
The following definitions comes from the Cochrane Handbook for Systematic Reviews of Interventions, Version 6.1.
"Systematic reviews seek to collate evidence that fits pre-specified eligibility criteria in order to answer a specific research question. They aim to minimize bias by using explicit, systematic methods documented in advance with a protocol." (chapter 1)
"Meta-analysis is the statistical combination of results from two or more separate studies." (chaptet 10)
A systematic review is a major commitment.
Cornell University Library's "What Type of Review Is Right for You?" can help you think through whether or not to embark on a systematic review or meta-analysis.