Why I Won't Talk to 'Fact Checkers' About Our Mask Study – The Daily Sceptic
The fact-checker of a powerful press syndicate asked Dr. Tom Jefferson to assist it in "debunking misrepresentations" of his recent Cochrane review finding no clear evidence masks work. Take a hike, he said.
You are right, they (cochrane) conduct and publish systematic reviews and meta analyses, not the primary studies themselves. And this is regarded as higher-order evidence than RCTs or any other method. The are regarded as best in the world.
(not all of their research is a meta analysis, the systematic review part essentially has to find enough studies that fit the criterea before that can be done)