For more than 10 years, researchers routinely complained that, because of the fast expansion of the scholarly literature, it was becoming very challenging for them to keep abreast of novel developments in even a very narrow portion of their discipline (e.g., Baveye 2014). At the same time, journal editors have experienced increasing difficulties to recruit reviewers (Siegel and Baveye 2010). Over the last few years, the situation does not appear to have improved significantly (West and Bergstrom 2021; Baveye 2021a, 2021b). The scholarly literature keeps expanding at an exponential rate. According to some estimates, 5.14 million articles were published during 2022, sizeably more than the 4.18 million published just 4 years earlier (Curcic 2023). More than ever, with conflicting demands on their time for teaching, supervising undergraduate and graduate students, reviewing for journals, or writing numerous proposals to compete for limited funding, researchers generally find it virtually impossible to devote as many hours as would be needed to read articles of direct interest to them in sufficient depth.
Not surprisingly in this context, a significant effort has unfolded to review and synthesise relatively large bodies of literature and make their content more readily accessible to researchers and policy-makers. In recent years, tens of thousands of systematic reviews and especially of “meta-analyses” have been written. The staggering scale of the endeavour is evinced by the fact that the article of Page et al. (2021), proposing revised reporting guidelines for meta-analyses, has already been cited over 79,000 times, in only 3 years, according to Google Scholar (https://scholar.google.com; Last retrieved, January 29, 2025). Because it is proving time-consuming to stay abreast even of meta-analyses in virtually all disciplines, a trend is currently emerging of synthesising meta-analyses via what has been referred to as “second-order” meta-analyses (e.g., Schmidt and Oh 2013; Bergquist et al. 2023), or of carrying out “overviews of systematic reviews” (Lunny et al. 2024). In 2023 alone, more than 7000 articles referred to these practices, according to Google Scholar.
No doubt part of the appeal of the meta-analysis method over the years has been its original description as a robust technique with a strong statistical foundation (Glass 1976; Shadish and Lecy 2015). Nevertheless, implementations of the method in practice have been the object of very strong criticisms, in particular in research on education (Abrami, Cohen, and d'Apollonia 1988; Ropovik, Adamkovic, and Greger 2021), medicine (Haidich 2010; Hedin et al. 2016; Chapman 2020), plant ecology (Koricheva and Gurevitch 2014), agronomy (Philibert, Loyce,