LAUSR

This study explores the extent that international research collaboration indicators vary according to two factors: countries' global economic levels and type of disciplines. The study examines the case of asymmetric co‐authorship relationships between the United States and its collaborative research countries, measured by the affinity index. The study finds that there is no significant interaction between the two factors surveyed. The discipline factor has a main effect on the asymmetric co‐authorship relationships. No main effect of the country factor categorised by economic level is found, after allowing for the discipline factor. This study contributes to the social science research on the impact of factors on co‐authorship in international research collaboration measurement indicators.