Geographic Origin of Publications in Radiological Journals as a Function of GDP and Percentage of GDP Spent on Research

Rationale and Objectives: The aim of this study was to examine the geographic origin of publications in the highest impacting radiology journals and to examine the link between the percentage of gross domestic product (GDP) spent on research by a country and the output of radiology publications. Materials and Methods: The five highest impacting general radiology journals (according to the ISI Web of Knowledge database) were selected over a 6-year period from January 2002 to December 2007. Publications were totaled according to the country of the corresponding author. Publications (total and corrected for population size) were assessed according to the GDP of a given country and the percentage of GDP spent on research in that country. Correlation was determined using Spearman's rank. Results: In total, 10,925 papers were identified. The top 10 nations produced 83.9% of the total number of papers. The United States was the most prolific country, with 41.7% of the total. The second-ranked and third-ranked countries were Germany (11.6%) and Japan (6.7%). Corrected for GDP, smaller European countries outperformed larger nations. Switzerland (0.925 publications per billion of GDP), Austria (0.694 publications per billion of GDP), and Belgium (0.648 publications per billion of GDP) produced the most papers per billion of GDP. When corrected for percentage of GDP spent on research, European countries again ranked highest, with Greece, Turkey, and Belgium having the best ratios. The percentage of GDP spent on research was positively correlated with the number of publications in high-ranking radiology journals (r = 0.603, P < .001). Conclusions: The United States is the most productive country in absolute number of publications. The flaws of using population size to compare publication output are clear, and a comparison using GDP and the percentage of GDP spent on research may give more meaningful results. When GDP is taken into consideration, smaller European countries are more productive. The importance of investment in radiologic research is emphasized by the association between increased funding of research and the number of publications in high-impacting radiology journals.