Evidence synthesis is a type of methodology that involves gathering primary research or individual studies, pulling data from those studies, and analyzing or synthesizing the results towards answering a specific research question. They use systematized and transparent methodologies with the aim of improving rigor, reducing bias, and ensuring reproducibility. In short, an evidence synthesis review is a study of studies.
From "A typology of reviews: an analysis of 14 review types and associated methodologies" (Grant & Booth, 2009).
A generic term for projects that gather published materials to provide an examination of a topic. They may or may not include comprehensive searches and quality assessment. They typically use narrative synthesis. Thus they are sometimes referred to as narrative reviews. Analysis could be thematic, chronological, etc.
These use a systematic, transparent approach to search for, appraise, and synthesize evidence. Their searches should be exhaustive and comprehensive. Inclusion of studies may be determined or weighed by quality assessment. They typically use both narrative and tabular synthesis. They may or may not include meta-analysis, a statistical method of combining the results of quantitative studies.
Scoping reviews are used to prepare for a future project by assessing the potential size and scope of available research on a topic. They typically use both narrative and tabular synthesis to characterize the quantity and quality of research.
A rapid review is used to assess what it already known about a policy or practice. It uses systematic review methods, but on a shorter timeframe. Thus some steps of the systematic review process may be skipped, such as the quality assessment.
For even more review types, check out the articles below.