A Systematic Review (SR) is a tool of quantitative research methodology that, through a systematic search and analysis of the literature, aims to answer to a research question. In fact, after identyfing all the literature relevant for contents and study design, it collects and analyses data from the studies included in the review. [1]
A SR can include a meta-analysis, that allows to synthesize the quantitative data from the studies included into a single statistical analysis. The presence or not of a metanalysis depends mostly on criteria such as the homogeneity and quantity of the studies.