Abstract Existent scientific literature diverges on the issue of open-access citation advantage, as available studies often employ different methods and were carried out at different periods. To reconcile previous divergent results, we ran several analysis concerning the proportion between open-access and non-open-access articles, and the citation advantage in Elsevier’s Hybrid journals which were active in the years Sci-Hub was being updated (from 2011 to dec/2021) and after it ceased updating (from jan/2022 to 2025). We relied on databases downloaded from the Directory of Open Journals (DOAJ) and Web of Science (WoS), including 233 journals and nearly 298.000 articles published from 2011 to 2025. The statistical tools employed consisted of linear univariate regression for trend analysis and the Wilcoxon rank sum for evaluating differences. We conclude the number of open-access articles per journal has been increasing steadily in this period and that 97% of the articles in our sample from 2011 to 2021 labelled as paywalled are available at Sci-Hub. Concerning citation advantage of open-access articles, we found no explanation for why some journals have a citation advantage in certain years, because they could not be grouped by JIF (Journal Impact Factor) percentile nor by journal size, so the advantage appears to be random. Additionally, when the advantage was significant, the effect size was small which, in our opinion, suffices to declare that we found no traces of a citation advantage for Hybrid Gold articles.
Perry et al. (Sat,) studied this question.