Coauthorship patterns and trends in the sciences : a bibliometric study with implications for database indexing and search strategies - 1980-1998

Library Trends, Wntr, 2002 by Wolfgang Glanzel

ABSTRACT

THE PRESENT STUDY AIMS AT describing both the common and the distinguishing features of coauthorship trends and patterns in selected science fields. The relation between coauthorship schemes and other bibliometric features, such as publication activity and citation impact are analyzed. I show that, while copublication activity has grown considerably, the extent of co-authorship and its relation with productivity and citation impact largely varies among fields. Besides universally valid tendencies, subject specific features can be found.

INTRODUCTION

Authorship is a primary bibliometric descriptor of a scientific publication. Its trends and patterns characterize the social and even the cognitive structure of research fields. The most characteristic tendency of recent times is intensifying scientific collaboration. Collaboration in research is reflected by the corresponding coauthorship of published results, and can thus be analyzed with the help of bibliometric methods.

Kretschmer has conducted profound analyses of coauthorship patterns as a function of the authors' productivity (e.g., Kretschmer, 1994). She concluded that, in invisible colleges, coauthorship between scientists with the same number of publications is more frequent than between authors of different publication activity and that the opposite is valid in institutionalized communities. On the other hand, the reverse question, whether higher "cooperativity" of authors exhibits a greater publication activity, has little been dealt with so far. The relation between collaboration and productivity was first studied by Beaver & Rosen (1979). The authors analyzed scientific papers of the French elite in the early eighteenth century, and concluded that collaboration is associated with higher productivity. In a recent paper, Braun, Glanzel, & Schubert (2001) have analyzed the relation between cooperativity and productivity in different author categories in the field of neurosciences. In the following study, I extend some of these results to broader science fields.

Bibliometric meso and macro studies concerned with the analysis of copublication patterns at the institutional (e.g., Hicks, Ishizuka, Keen, & Sweet, 1994; Hicks & Katz, 1997), and the national level (Gomez, Fernandez, & Mendez, 1995; REIST-2, 1997; Glanzel, 2001) have shown a growing copublication activity. This applies to both scientific collaboration between industry and universities and research cooperation at the domestic, national, and supra-national level. These studies have also proved that international collaboration is--at least on the average--associated with a higher citation impact.

Besides economic and political factors, intra-scientific factors (e.g., Luukkonen, Persson, & Silvertsen, 1992), especially changing communication patterns and increasing mobility of scientists, are influencing collaboration. These factors motivate cooperation in "less expensive" areas, such as pure mathematics, and theoretical research in social sciences, too. The growing share of copublications in theoretical fields could be substantiated in the named literature.

The question arises whether one can observe the same tendencies also at the lowest level of aggregation, that is, at the level of individual publications and of authors. In the light of the above considerations, the following three questions will be answered:

* Does the development of coauthorship at the micro level, that is, at the level of individual papers, follow the trend of intensifying collaboration found at the meso (institutional) and macro (i.e., national and supra-national) level, particularly in the context of international research collaboration?

* Has the cooperativity any influence upon the authors' productivity?

* Do multiauthored papers exhibit a greater citation impact than publications with single authors?

These issues have to be addressed and answered at each level of aggregation separately since the results by Gomez, Fernandez, & Mendez (1995) and Katz (2000) have shown that different types of collaboration may exhibit contradictory effects. For instance, while some types of collaboration exhibit Matthew effect, others exhibit the inverse effect (see Katz, 2000). Therefore, conclusions made for a higher level of aggregation cannot be simply assigned to a lower one and vice versa. Consequently, the results of the following analysis should not be generalized as being valid for all types of scientific collaboration.

DATA SOURCES

All papers recorded in the annual volumes of the Science Citation Index (SCI) of the Institute for Scientific Information (ISI) as article, letter, note, or review were taken into consideration. For instance, documents of the type corrections, editorial material, bibliographical items, meeting abstracts, book reviews, news items, etc. have been omitted. The latter types are from the bibliometric viewpoint not considered conveyers of relevant scientific information related to original research results, and are thus not regarded as citable items. All (co)authors indicated in the corresponding search field have been taken into account. Author names were taken as recorded into the database, no corrections have been made for spelling variants or for adjustment of homonyms.