The phrase that comes to mind is "literature review", but that's not it. I'm looking for the word one would use in an academic context to describe a research study which pulls data from, ideally, all previous studies done to address a particular matter.
For example, suppose one wanted to address the question "Does egg consumption increase the risk of heart disease?". What one could do is, do a massive literature review round up all previous studies which have directly answered this question. Then select the papers which fit your criteria for eligibility (as many as possible), and then do statistics on the results from all these studies, sort of combining them all into one mega-study.