Scientific Collaboration across Time and Space: Bibliometric Analysis of the American Journal of Neuroradiology, 1980–2018

BACKGROUND AND PURPOSE: Scientific collaboration is traditionally acknowledged through coauthorship. Studies on this topic are few in the neuroimaging literature. This study is a bibliometric analysis of the American Journal of Neuroradiology (AJNR) between 1980 and 2018, with the primary aim of evaluating changes in article collaboration.

MATERIALS AND METHODS: Full bibliographic records from 1980 to 2018 were retrieved. Yearly metrics calculated included the number of articles published, the average number of authors, and the average number of affiliations per article. The levels of evidence of 160 random articles were determined. Geographic characteristics of author affiliations were analyzed. Changes across time were evaluated using linear regression, while Spearman rank-order correlation was used to determine relationships between level of evidence and time, number of authors, and number of affiliations.

RESULTS: There was a steady linear growth in the number of articles (R² = 0.70, P < 1e–10) from 1980 to 2018. There were clear linear increases in the average number of authors (R² = 0.91, P < 1e–15) and affiliations (R² = 0.90, P < 1e–15) per article. There was a significant correlation between level of evidence and time period (Spearman ρ = −0.42, P < 1e−7), indicating that articles trended toward better methodologic quality or strength of results over time. A significant correlation existed between the level of evidence and the number of authors (Spearman ρ = −0.39, P < 1e–6). There were linear increases in the average number of different geographic locales of authors per article by country/region (R² = 0.80, P < 1e–13), state/province (R² = 0.88, P < 1e–15), and locality/city/town (R² = 0.86, P < 1e–15).

CONCLUSIONS: From 1980 to 2018, as the quantity of articles published in the AJNR increased, their level of evidence improved, while an increasing number of authors with different affiliations and from different geographic locales collaborated on these articles.