Grey system theory trends from 1991 to 2018: a bibliometric analysis and visualization

Grey system theory has rapidly developed in recent years, and it has solved real-world problems in various scientific fields successfully. However, there is a lack of bibliometric analysis and visualization on grey system theory from a quantitative perspective. This paper provides quantitative insights into the general landscape of the theory over the last 27 years, aiming to develop a meaningful overview for scholars interested in studying grey system theory. We screen out 4859 publications from Web of Science Core Collection to present a relatively comprehensive review. Software tools such as Citespace, Statplanet, and Gephi are adopted to conduct a series of studies. Major findings are as follows: Firstly, the most significant developments occurred in China, Taiwan, and the USA. Especially China has occupied a dominant position in this theory, recorded the highest counts and established close cooperative relationships with many countries or regions. Secondly, several universities and research institutions play vital roles in collaboration networks, while the most influential core authors are eastern scientists. Thirdly, research hotspots shift away from high concentration to diversification and therefore the existing research fields are extensive. Finally, through direct citation and co-citation analysis, citation burst detection and co-citation clusters evolution analysis, we identify and visualize key literature, milestones in the history of theoretical development, research hotspots and trends. This empirical study has significance for establishing a landscape of grey system theory through outlining the dynamic evolution process of the knowledge clusters.