Research Design, Methodology, & Questions

The literature search was initially based on our earlier study (Lefley & Janeček, 2025), which we updated to include articles from the Scopus database by the end of December 2024, using the same criteria. The search resulted in 226 articles. Book chapters (9), conference papers (2), and reviews (2) were deleted, leaving 213 articles. A journal editor retracted one article, leaving 212. A further 41 were discarded as they were irrelevant to the current study (as we were looking for the support—or lack of—for the critical mass theory, in particular, the reasons for the lack of support), leaving a final sample of 171 articles covering the period from 2013 to the end of December 2024. Support for the critical mass theory was reported in 150 cases (87.7%), mixed support was observed in 14 cases (8.2%), and there was a lack of support in 7 cases (4.1%). We initially examined the seven articles that rejected the critical mass theory in more detail to identify the reasons for such rejection, specifically, the reasons for an ineffectual critical mass. We then examined the fourteen articles, which provided some support but were inconclusive. Further searches were made on the Scopus database, focusing on several relevant topics (conflict, female family directors, female attributes, etc.). We also drew on our past research knowledge on gender quotas. Only by identifying the lack of support for the critical mass theory can we start to conceptualise the underlying reasons for an ineffective critical mass and show that it is not just about the numbers. By identifying several conceptual threads, we were able to link them together to form a cohesive structure of ineffectual reasons for the lack of support for the critical mass theory. We have structured the article to clearly outline the research path (Lefley, 2006), which leads from the research issue of why a critical mass of female directors may be ineffective to the conceptualisations and conclusions.