Measures of international collaboration in scientific literature: Part I

Research evaluating models of scientific productivity require coherent metrics that quantify various key relations among papers as revealed by patterns of citation. This paper focuses on the various conceptual problems inherent in measuring the degree to which papers tend to cite other papers written by authors of the same nationality. We suggest that measures can be given a degree of assurance of coherence by being based on mathematical models describing the citation process. A number of such models are developed.