It is no secret – there are way too many meta-analyses while  original research is missing [blog, paper, paper, paper, paper,  journal, journal). Books are about the method are also abundant. Sure, armchair research can be done without getting dirty.

Narrative reviews are much less appreciated nowadays although most of the current “systematic reviews” are basically useless as they are frequently written by “new kids on the block” and not by experienced scientists.

If the  current pace continues, we will soon have more reviews than original studies… As another author put it forward it is a “bloated mushroom of evidence”.