IPBES Global Assessment Report

I selected one of IPBES's assessment reports, because I would like to talk about, how to study assessments from a data perspective. Global environmental assessments are special in this regard, because they do not directly generate new data, but aim at assessing existing knowledge and data in a research field. But in synthesizing this existing knowledge and data they also create new datasets that draw connections between studies (etc.). How can this multileveled relevance of data in my field be studied?