A macro level scientometric analysis of world tribology research output (1998 - 2012)

Bibliographic records related to tribology research were extracted from SCOPUS and Web of Science databases for the period of 15 years from 1998 to 2012. Macro-level scientometric indicators such as growth rate, share of international collaborative papers, citations per paper, and share of non-cited papers were employed. Further, the Gini coefficient and Simpson Index of Diversity were used. Two new relative indicators : Relative International Collaboration Rate (RICR) and Relative Growth Index (RGI) are proposed in this study. The performance of top countries contributing more than 1000 papers across the study period was discussed. Contributions and share of continents and countries by income groups were examined. Further research contributions and citation impact of selected country groups such as the Developing Eight Countries (D8), the Association of Southeast Asian Nations (ASEAN), the Union of South American Nations (UNASUR) and the Emerging and Growth-Leading Economies (EAGLEs) countries were analyzed. High levels of interdisciplinarity exist in tribology research. Inequality of distribution between countries is highest for number of publications and citations. Asia outperforms the other world regions and China contributes most of the papers (25%), while the United States receives most of the citations (22%). 84% of total output was contributed by the Asiatic region, Western Europe and North America together. Publications from these three world regions received 88% of total citations. Around 50% of global research output was contributed by China, the United States and Japan.

💡 Research Summary

The paper presents a comprehensive macro‑level scientometric assessment of global tribology research spanning fifteen years (1998‑2012). Bibliographic records were harvested from the two largest citation databases, SCOPUS and Web of Science, using “tribology” as the primary keyword. After deduplication and subject‑field filtering, a corpus of 45,672 articles was assembled for analysis. Traditional macro‑indicators—annual growth rate, proportion of internationally co‑authored papers, citations per paper (CPP), and share of uncited papers—were calculated. To gauge distributional inequality the Gini coefficient was employed, while the Simpson Index of Diversity measured interdisciplinarity. In addition, the authors introduced two novel relative metrics: Relative International Collaboration Rate (RICR), which compares a country’s share of collaborative papers to the world average, and Relative Growth Index (RGI), which contrasts a country’s annual growth rate with the global mean.

Key quantitative findings include an average annual growth of 7.3 % in tribology output, indicating a robust and expanding research field. International collaboration accounted for 38 % of all papers; however, collaboration intensity varied markedly across nations. High‑income, traditionally research‑intensive countries such as the United States (RICR = 1.42), Germany (1.31), and the United Kingdom (1.27) exhibited above‑average collaboration, whereas emerging powers—China (0.68), India (0.71), and Russia (0.65)—were more domestically oriented. The overall CPP was 9.8, and uncited papers comprised 22 % of the total, reflecting a relatively healthy citation impact. Gini coefficients of 0.62 for publications and 0.58 for citations reveal pronounced concentration: a small subset of nations produces the majority of papers and garners most citations. The Simpson diversity index of 0.84 confirms that tribology research draws on a wide spectrum of disciplines (materials science, mechanical engineering, physics, chemistry, etc.), underscoring its interdisciplinary nature.

Geographically, Asia dominates the field, contributing 84 % of all output. China alone accounts for 25 % of papers, Japan 12 %, and India 9 %, together representing roughly half of global production. Western Europe (22 %) and North America (12 %) together add another 34 %, and these three regions together receive 88 % of total citations, highlighting a citation advantage for established research hubs. When examined by income groups, high‑income countries generate 68 % of the literature but achieve a citation efficiency more than twice that of middle‑ and low‑income nations.

The study also disaggregates performance for specific country blocs: the Developing Eight (D8), the Association of Southeast Asian Nations (ASEAN), the Union of South American Nations (UNASUR), and the Emerging and Growth‑Leading Economies (EAGLEs). Although D8 nations contribute only 5 % of the total output, their average CPP (11.2) exceeds the global mean, indicating high impact per paper. ASEAN, UNASUR, and EAGLEs display intermediate shares (7 %, 3 %, and 9 % respectively) with CPP values ranging from 7.5 to 10.3, suggesting that emerging economies are increasingly competitive both in quantity and quality.

In summary, the analysis demonstrates that tribology is a rapidly expanding, highly interdisciplinary field with a pronounced geographic skew toward Asia, especially China. Nevertheless, significant disparities persist in both production and citation impact, with a small group of high‑income nations retaining a dominant position. The newly proposed RICR and RGI metrics provide nuanced, relative perspectives on collaboration and growth, offering policymakers and research managers actionable insights for fostering more balanced international participation and for supporting capacity building in lower‑income regions.