as a tool for evidence synthesis. The first example of this was by Hans Eysenck, who, in a 1978 article in response to the work done by Smith and Glass, called meta-analysis an "exercise in mega-silliness". Later, Eysenck would refer to meta-analysis as "statistical alchemy". Despite these criticisms, the use of meta-analysis has only grown since its introduction. By 1991, there were 334 published meta-analyses, had grown to 9,135 by 2014.

The field of meta-analysis