This article examines the rise in co-authorship in the Social Sciences over a 34-year period. It investigates the development in co-authorship in different research fields and discusses how the methodological differences in these research fields together with changes in academia affect the tendency to co-author articles. The study is based on bibliographic data about 4.5 million peer review articles published in the period 1980-2013 and indexed in the 56 subject categories of the Web of Science's (WoS) Social Science Citation Index (SSCI). The results show a rise in the average number of authors, share of co-authored and international co-authored articles in the majority of the subject categories. However, the results also show that there are great disciplinary differences to the extent of the rises in co-authorship. The subject categories with a great share of international co-authored articles have generally experienced an increase in co-authorship, but increasing international collaboration is not the only factor influencing the rise in co-authorship. Hence, the most substantial rises have occurred in subject categories, where the research often is based on the use of experiments, large data set, statistical methods and/or team-production models.

The number of co-authors has in the social sciences has been rising over the last decades, but a deeper understanding of why this rise is occurring is lacking. Previous studies of co-authorship in the social sciences often refer to the physical or life sciences or anecdotal evidence to explain these changes. This article examines the relationship between changes in co-authorship and research in Danish economics and political science to gain greater insights into whether there are changes in the research or in researchers' behavior. The analysis shows that articles with empirical research, quantitative research and/or survey are more likely to have a higher number of co-authors than articles based on theoretical, interview, and qualitative research. Furthermore, international and interinstitutional Danish articles tend to have more co-authors than interinstitutional articles. The analysis also reveals that the average number of authors increases for articles with all types of research and research approaches. This indicates that the collaboration behavior of the researchers is changing.

Researchers have different ways of deciding on the author order, and how they do it often depends on the culture of their field. Some fields are well known for using alphabetic author order, while others put a great emphasis on the meaning of the author order and place authors according to contribution. This article is the first to use mixed method to examine the extent of alphabetic author order and to examine why researchers adopt a certain author order norm in the fields of economics and political science. The article finds that alphabetic authorship has been and is the norm in economics, while some tendency towards it exists in political science. The differences in the intellectual and social organization of the fields seem to be a factor in the extent that these researchers will adopt a certain norm. Furthermore, the increasing number of authors per article and the publish‐or‐perish culture seems to put pressure on the alphabetic norm because it creates greater attention to the reputational advantages of being first‐author.